The call stack for that code path failing is:

#0  get_data (fp=0xf64920, archive=0xe77ecc "/home/greg/sandbox/python/cpython/2.7/junk95142.zip", 
    toc_entry=('/home/greg/sandbox/python/cpython/2.7/junk95142.zip/ziptestpackage/ziptestmodule.py', 0, 16, 16, 0, 344, 17462, -1268077639)) at ./Modules/zipimport.c:1038
#1  0x00000000005401b3 in get_code_from_data (archive=0xe77ecc "/home/greg/sandbox/python/cpython/2.7/junk95142.zip", 
    fp=0xf64920, ispackage=0, isbytecode=0, mtime=0, 
    toc_entry=('/home/greg/sandbox/python/cpython/2.7/junk95142.zip/ziptestpackage/ziptestmodule.py', 0, 16, 16, 0, 344, 17462, -1268077639)) at ./Modules/zipimport.c:1267
#2  0x00000000005404a9 in get_module_code (self=0xe6b6f0, fullname=0xe6f0ec "ziptestpackage.ziptestmodule", 
    p_ispackage=0x7fffffff98d8, p_modpath=0x7fffffff98e8) at ./Modules/zipimport.c:1325
#3  0x000000000053dd77 in zipimporter_load_module (obj=<zipimport.zipimporter at remote 0xe6b6f0>, 
    args=('ziptestpackage.ziptestmodule',)) at ./Modules/zipimport.c:352
#4  0x00000000005646b8 in PyCFunction_Call (
    func=<built-in method load_module of zipimport.zipimporter object at remote 0xe6b6f0>, 
    arg=('ziptestpackage.ziptestmodule',), kw=0x0) at Objects/methodobject.c:81
#5  0x0000000000420f97 in PyObject_Call (
    func=<built-in method load_module of zipimport.zipimporter object at remote 0xe6b6f0>, 
    arg=('ziptestpackage.ziptestmodule',), kw=0x0) at Objects/abstract.c:2529
#6  0x00000000004210ed in call_function_tail (
    callable=<built-in method load_module of zipimport.zipimporter object at remote 0xe6b6f0>, 
    args=('ziptestpackage.ziptestmodule',)) at Objects/abstract.c:2561
#7  0x00000000004214f2 in PyObject_CallMethod (o=<zipimport.zipimporter at remote 0xe6b6f0>, 
    name=0x5a6c7d "load_module", format=0x5a6b67 "s") at Objects/abstract.c:2638
#8  0x00000000004f3aa0 in load_module (name=0xf67630 "ziptestpackage.ziptestmodule", fp=0x0, 
    pathname=0xf68660 "/home/greg/sandbox/python/cpython/2.7/junk95142.zip/ziptestpackage", type=9, 
    loader=<zipimport.zipimporter at remote 0xe6b6f0>) at Python/import.c:1961
#9  0x00000000004f5a67 in import_submodule (mod=<module at remote 0xe6c8e8>, subname=0xf6763f "ziptestmodule", 
    fullname=0xf67630 "ziptestpackage.ziptestmodule") at Python/import.c:2700
#10 0x00000000004f5037 in load_next (mod=<module at remote 0xe6c8e8>, altmod=<module at remote 0xe6c8e8>, 
    p_name=0x7fffffff9c88, buf=0xf67630 "ziptestpackage.ziptestmodule", p_buflen=0x7fffffff9ca0)
    at Python/import.c:2515