Well if it works now, and if the problem doesn't occur anymore, it's OK...
But I would like to know exactly when the error happened? Did you restart MSN after install? Did it crash right after typing /xcolornick ? or was it during loading ... ?
[note: updated ColorNick at
http://crespel.chez.tiscali.fr/download/CNsetup.exe -> Function name in the title of the error Msgbox to help solving problems]
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Mithrandir