MSN Messenger "the parameter is incorrect"

I recently went ahead and upgraded MSN Messenger even
though I already had 6.1. I had been getting a message
that there was a new release. Didn't make sense but I
wanted to get rid of the recurrring message. Since then,
Messenger often (50%) does not load on boot as it is set
to do. I reboot and it is back. The bigger problem is
that when I try to bring it up as a program so that I
don't have to reboot, I get an error message "the
parameter is incorrect". I fully removed the program and
re-downloaded. That I did not resolve the problem. My
computer is a Toshiba 1805-s274 laptop with Windows XP
Home.