Ran test_winreg on VC6 to get threaded stack trace. But it happened on VS8 too.

////////////////////////////////////////
// Thread-1

NTDLL! 77f935dd()
PyEnumValue(_object * 0x00000000, _object * 0x00c40438) line 1230 + 36 bytes
PyCFunction_Call(_object * 0x00c40678, _object * 0x00c40438, _object * 0x00000000) line 81 + 11 bytes
call_function(_object * * * 0x0022e394, int 12846136) line 4012 + 200 bytes
PyEval_EvalFrameEx(_frame * 0x00966c88, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00b0bbc8, _object * 0x00966c88, _object * 0x00000001, _object * * 0x00000018, int 1, _object * * 0x00965fcc, int 1, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
fast_function(_object * 0x00000000, _object * * * 0x0022e52c, int 1, int 1, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0022e52c, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x00965e58, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00b47c28, _object * 0x00965e58, _object * 0x00000002, _object * * 0x00c4040c, int 2, _object * * 0x009c104c, int 0, _object * * 0x00bbbef4, int 1, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00bbdf58, _object * 0x00c403f8, _object * 0x00c4d188) line 531 + 58 bytes
PyObject_Call(_object * 0x00bbdf58, _object * 0x00c403f8, _object * 0x00c4d188) line 2522 + 15 bytes
ext_do_call(_object * 0x00c403f8, _object * * * 0x0022e700, int 3, int 1, int 0) line 4325 + 8 bytes
PyEval_EvalFrameEx(_frame * 0x00964098, int 1) line 2707
PyEval_EvalCodeEx(PyCodeObject * 0x00b47da8, _object * 0x00964098, _object * 0x00000001, _object * * 0x00c403cc, int 2, _object * * 0x00000000, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00bbf038, _object * 0x00c403b8, _object * 0x00000000) line 531 + 58 bytes
PyObject_Call(_object * 0x00bbf038, _object * 0x00c403b8, _object * 0x00000000) line 2522 + 15 bytes
instancemethod_call(_object * 0x00bbf038, _object * 0x00c403b8, _object * 0x00000000) line 2578 + 17 bytes
PyObject_Call(_object * 0x00c19a78, _object * 0x00c46e70, _object * 0x00000000) line 2522 + 15 bytes
slot_tp_call(_object * 0x00c46850, _object * 0x00c46e70, _object * 0x00000000) line 5388 + 17 bytes
PyObject_Call(_object * 0x00c46850, _object * 0x00c46e70, _object * 0x00000000) line 2522 + 15 bytes
do_call(_object * 0x00c46850, _object * * * 0x0022eb94, int 1, int 12873328) line 4230 + 11 bytes
call_function(_object * * * 0x0022eb94, int 0) line 4035 + 15 bytes
PyEval_EvalFrameEx(_frame * 0x00964cc8, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00bb1e08, _object * 0x00964cc8, _object * 0x00000003, _object * * 0x0096340c, int 3, _object * * 0x00963418, int 0, _object * * 0x00bc46a4, int 1, _object * 0x00000000) line 3252 + 11 bytes
fast_function(_object * 0x00000001, _object * * * 0x0022ed2c, int 3, int 3, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0022ed2c, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x009632b8, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00bb1e08, _object * 0x009632b8, _object * 0x00000002, _object * * 0x009635c0, int 2, _object * * 0x009635c8, int 0, _object * * 0x00bc46a4, int 1, _object * 0x00000000) line 3252 + 11 bytes
fast_function(_object * 0x00000001, _object * * * 0x0022eec4, int 2, int 2, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0022eec4, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x00963478, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00bb1c88, _object * 0x00963478, _object * 0x00000002, _object * * 0x00c4034c, int 2, _object * * 0x009c104c, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00bc2a88, _object * 0x00c40338, _object * 0x00c4d0e0) line 531 + 58 bytes
PyObject_Call(_object * 0x00bc2a88, _object * 0x00c40338, _object * 0x00c4d0e0) line 2522 + 15 bytes
ext_do_call(_object * 0x00c40338, _object * * * 0x0022f098, int 3, int 1, int 0) line 4325 + 8 bytes
PyEval_EvalFrameEx(_frame * 0x00963628, int 1) line 2707
PyEval_EvalCodeEx(PyCodeObject * 0x00bb19e8, _object * 0x00963628, _object * 0x00000001, _object * * 0x00c4020c, int 2, _object * * 0x00000000, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00bc29d8, _object * 0x00c401f8, _object * 0x00000000) line 531 + 58 bytes
PyObject_Call(_object * 0x00bc29d8, _object * 0x00c401f8, _object * 0x00000000) line 2522 + 15 bytes
instancemethod_call(_object * 0x00bc29d8, _object * 0x00c401f8, _object * 0x00000000) line 2578 + 17 bytes
PyObject_Call(_object * 0x00c19bb8, _object * 0x00c46b60, _object * 0x00000000) line 2522 + 15 bytes
slot_tp_call(_object * 0x00c46540, _object * 0x00c46b60, _object * 0x00000000) line 5388 + 17 bytes
PyObject_Call(_object * 0x00c46540, _object * 0x00c46b60, _object * 0x00000000) line 2522 + 15 bytes
do_call(_object * 0x00c46540, _object * * * 0x0022f52c, int 1, int 12872544) line 4230 + 11 bytes
call_function(_object * * * 0x0022f52c, int 0) line 4035 + 15 bytes
PyEval_EvalFrameEx(_frame * 0x009623d8, int 131) line 2667
fast_function(_object * 0x00000000, _object * * * 0x0022f674, int 2, int 2, int 9181632) line 4099
call_function(_object * * * 0x0022f674, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x00962e88, int 131) line 2667
fast_function(_object * 0x00000000, _object * * * 0x0022f7bc, int 1, int 1, int 9181632) line 4099
call_function(_object * * * 0x0022f7bc, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x0095fb18, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00bf7448, _object * 0x0095fb18, _object * 0x00000000, _object * * 0x0095fe1c, int 3, _object * * 0x0095fe28, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
fast_function(_object * 0x00000000, _object * * * 0x0022f954, int 3, int 3, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0022f954, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x0095fcd8, int 131) line 2667
fast_function(_object * 0x00000000, _object * * * 0x0022fa9c, int 0, int 0, int 9181632) line 4099
call_function(_object * * * 0x0022fa9c, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x009236c8, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00b381a8, _object * 0x009236c8, _object * 0x00a102d8, _object * * 0x00000000, int 0, _object * * 0x00000000, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
PyEval_EvalCode(PyCodeObject * 0x00b381a8, _object * 0x00a102d8, _object * 0x00a102d8) line 671 + 31 bytes
exec_statement(_frame * 0x00922198, _object * 0x00b381a8, _object * 0x00a102d8, _object * 0x00a102d8) line 4709 + 8 bytes
PyEval_EvalFrameEx(_frame * 0x00922198, int 10552024) line 1881
PyEval_EvalCodeEx(PyCodeObject * 0x00a481a8, _object * 0x00922198, _object * 0x00000007, _object * * 0x008f4e10, int 7, _object * * 0x008f4e2c, int 0, _object * * 0x00b03c64, int 5, _object * 0x00000000) line 3252 + 11 bytes
fast_function(_object * 0x00000005, _object * * * 0x0022fdbc, int 7, int 7, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0022fdbc, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x008f4ca8, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00a873e8, _object * 0x008f4ca8, _object * 0x00000002, _object * * 0x00b0054c, int 2, _object * * 0x00000000, int 0, _object * * 0x00b07c1c, int 1, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00b0c090, _object * 0x00b00538, _object * 0x00000000) line 531 + 58 bytes
PyObject_Call(_object * 0x00b0c090, _object * 0x00b00538, _object * 0x00000000) line 2522 + 15 bytes
RunModule(char * 0x008c1b20, int 1) line 182 + 15 bytes
Py_Main(int 3, char * * 0x008c1b60) line 546 + 11 bytes
main(int 3, char * * 0x008c1b60) line 23 + 14 bytes
mainCRTStartup() line 338 + 17 bytes
KERNEL32! 77e789d5()

////////////////////////////////////////
// Thread-2

NTDLL! 77f88de7()
ADVAPI32! 7949e920()
ADVAPI32! 79483f47()
PySetValue(_object * 0x00000000, _object * 0x00c485d8) line 1581 + 27 bytes
PyCFunction_Call(_object * 0x00c40978, _object * 0x00c485d8, _object * 0x00000000) line 81 + 11 bytes
call_function(_object * * * 0x0130f904, int 12879320) line 4012 + 200 bytes
PyEval_EvalFrameEx(_frame * 0x00967288, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00b0baa8, _object * 0x00967288, _object * 0x00000001, _object * * 0x009675a8, int 1, _object * * 0x009675ac, int 0, _object * * 0x00000000, int 0, _object * 0x00c46fc0) line 3252 + 11 bytes
fast_function(_object * 0x00000000, _object * * * 0x0130fa9c, int 1, int 1, int 0) line 4111 + 53 bytes
call_function(_object * * * 0x0130fa9c, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x00967458, int 131) line 2667
fast_function(_object * 0x00000000, _object * * * 0x0130fbe4, int 1, int 1, int 9850976) line 4099
call_function(_object * * * 0x0130fbe4, int 0) line 4033 + 16 bytes
PyEval_EvalFrameEx(_frame * 0x00967628, int 131) line 2667
PyEval_EvalCodeEx(PyCodeObject * 0x00c37ce8, _object * 0x00967628, _object * 0x00000001, _object * * 0x00c465c4, int 1, _object * * 0x00000000, int 0, _object * * 0x00000000, int 0, _object * 0x00000000) line 3252 + 11 bytes
function_call(_object * 0x00c42a30, _object * 0x00c465b0, _object * 0x00000000) line 531 + 58 bytes
PyObject_Call(_object * 0x00c42a30, _object * 0x00c465b0, _object * 0x00000000) line 2522 + 15 bytes
instancemethod_call(_object * 0x00c42a30, _object * 0x00c465b0, _object * 0x00000000) line 2578 + 17 bytes
PyObject_Call(_object * 0x00c4c438, _object * 0x009c1038, _object * 0x00000000) line 2522 + 15 bytes
PyEval_CallObjectWithKeywords(_object * 0x00c4c438, _object * 0x009c1038, _object * 0x00000000) line 3882
t_bootstrap(void * 0x00a36668) line 615 + 26 bytes
bootstrap(void * 0x00251278) line 122 + 7 bytes
_threadstartex(void * 0x009610d0) line 212 + 13 bytes
KERNEL32! 77e5b3bc()