+Index: Lib/python/pyrun.swg
+===================================================================
+RCS file: /cvsroot/swig/SWIG/Lib/python/pyrun.swg,v
+retrieving revision 1.53
+diff -u -4 -r1.53 pyrun.swg
+--- Lib/python/pyrun.swg 11 Dec 2004 23:38:44 -0000 1.53
++++ Lib/python/pyrun.swg 15 Apr 2005 23:11:25 -0000
+@@ -455,9 +455,10 @@
+ } else {
+ PyErr_Format(PyExc_TypeError, "a '%s' is expected, '%s' is received",
+ type, otype);
+ }
+- Py_DECREF(str);
++ if (str)
++ Py_DECREF(str);
+ return;
+ }
+ }
+ PyErr_Format(PyExc_TypeError, "a '%s' is expected", type);