Hi Juan Bengoa,
I believe Matty's response was correct, and that it is the handwriting plug-in that is causing the problem, but that you might not have done what was needed to solve the problem. Make sure you did the unchecking just like Matty suggested.
If that doesn't work, then close down all Messenger related applications (press ctrl-alt-delete and end the tasks 'msmsgr.exe', 'msgplus.exe' and 'msnmsgr.exe' if you see them) and remove the file MsnHandWriting.dll from your Messenger Plus!\Plugins directory, most likely the default C:\Program Files\Messenger Plus! 3\Plugins.
More information can be found at
http://shoutbox.menthix.net/showthread.php?tid=22276, it's the link Matty also gave. I suggest you read that, if you haven't done so.
This should solve your problem
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