After months, I finally found a solution to this problem
. First uninstal MsgPlus, after you removed it be sure that MSN Messenger is not running, go in the "Program Files" dir, and then copy and paste the "MSN Messenger" directory, in this manner you should obtain another dir called "Copy of MSN Mesenger" or something like that. Now rename "MSN Mesenger" in "MSN Mesenger2", and then rename "Copy of MSN Mesenger" in "MSN Mesenger". At this point try to reinstall MsgPlus. For me this worked, even if it has no sense
p.s.
Sorry for my english, but i'm italian
