diff -r a48d256cc7d9 -r b0b19d61d79a hgext/mq.py
--- a/hgext/mq.py	Thu Mar 04 13:11:29 2010 +0100
+++ b/hgext/mq.py	Thu Mar 04 14:23:54 2010 +0100
@@ -813,7 +813,8 @@
     _reserved = ('series', 'status', 'guards')
     def check_reserved_name(self, name):
         if (name in self._reserved or name.startswith('.hg')
-            or name.startswith('.mq')):
+            or name.startswith('.mq') or '#' in name
+            or (os.name == 'nt' and ':' in name)):
             raise util.Abort(_('"%s" cannot be used as the name of a patch')
                              % name)