diff -r ed73006bac42 Modules/_tkinter.c
--- a/Modules/_tkinter.c	Tue Mar 13 13:50:34 2012 +0100
+++ b/Modules/_tkinter.c	Tue Mar 13 11:09:44 2012 -0700
@@ -613,6 +613,13 @@
     }
 #endif
 #ifdef WITH_THREAD
+    if (!(v->threaded)) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "Tcl/Tk was not compiled with --enable-threads but "
+                        "Python has threads enabled");
+        Py_DECREF(v);
+        return 0;
+    }
     if (v->threaded && tcl_lock) {
         /* If Tcl is threaded, we don't need the lock. */
         PyThread_free_lock(tcl_lock);