Yeah I think you are using the wrong version of the patch. If you go here
http://patch.mess.be/?p=download and then from the drop down under version history select 8.1.
Also note:
QUOTE (mess.be mess patch downloads)
Make sure you are patching an original unmodifed Windows Live Messenger (no skins, other patches, etc...). If you want to patch Windows Live Messenger more than once don't forget to restore your backups each time.