diff --git a/isapi/threaded_extension.py b/isapi/threaded_extension.py
index b31c8c9e7..0e89da583 100644
--- a/isapi/threaded_extension.py
+++ b/isapi/threaded_extension.py
@@ -165,11 +165,12 @@ def HandleDispatchError(self, ecb):
                 list = traceback.format_tb(
                     exc_tb, limit
                 ) + traceback.format_exception_only(exc_typ, exc_val)
+                bold = list.pop()
                 print(
                     "<PRE>%s<B>%s</B></PRE>"
                     % (
-                        cgi.escape("".join(list[:-1])),
-                        cgi.escape(list[-1]),
+                        cgi.escape("".join(list)),
+                        cgi.escape(bold),
                     ),
                     file=ecb,
                 )