Index: message.py
===================================================================
--- message.py	(revision 62468)
+++ message.py	(working copy)
@@ -436,7 +436,7 @@
         if value is missing:
             # This should have no parameters
             return self.get_default_type()
-        ctype = paramre.split(value)[0].lower().strip()
+        ctype = value.split(";", 1)[0].lower().strip()
         # RFC 2045, section 5.2 says if its invalid, use text/plain
         if ctype.count('/') <> 1:
             return 'text/plain'