diff --git a/Mac/Modules/cf/cfsupport.py b/Mac/Modules/cf/cfsupport.py
index bb0ac40..e8fb710 100644
--- a/Mac/Modules/cf/cfsupport.py
+++ b/Mac/Modules/cf/cfsupport.py
@@ -360,7 +360,7 @@
 		if (v == Py_None) { *p_itself = NULL; return 1; }
 		if (PyString_Check(v)) {
 		    char *cStr;
-		    if (!PyArg_Parse(v, "et", "ascii", &cStr))
+		    if (!PyArg_Parse(v, "es", "ascii", &cStr))
 		    	return NULL;
 			*p_itself = CFStringCreateWithCString((CFAllocatorRef)NULL, cStr, kCFStringEncodingASCII);
 			return 1;
diff --git a/Mac/Modules/cf/pycfbridge.c b/Mac/Modules/cf/pycfbridge.c
index d4466ac..21a9522 100644
--- a/Mac/Modules/cf/pycfbridge.c
+++ b/Mac/Modules/cf/pycfbridge.c
@@ -292,7 +292,7 @@
 	UniChar *unichars;
 	
 	if (PyString_Check(src)) {
-		if (!PyArg_Parse(src, "es", NULL, &chars))
+		if (!PyArg_Parse(src, "es", "ascii", &chars))
 			return NULL; /* This error is more descriptive than the general one below */
 		*dst = CFStringCreateWithCString((CFAllocatorRef)NULL, chars, kCFStringEncodingASCII);
 		return 1;