Error 629

When I want to dial into my ISP, after I had enter in my user ID and password, there is a message saying that”Verifying username and password. After that, it will disconnect by itself with an error code” 629″. As such, I reinstall my modem driver tothe latest version and I’m able to log into internet successfully.But when I reboot my PC, the problem came back again. I believe there is corrupted DLL file which causing all this problem. I hope to solve the problem without reinstall win98. Any one can help mi?