From the description of the problem, it sounded like the successful establishment of a VPN session occurs with a different username/password on the same PC.

I wonder if the failed username is a member of the same VPN group as the succesful username. Otherwise, I would check your authentication server to see why the authentication is failing.

Slmansfield,

Correct, it's possible to connect on the same computer with a different username and password.

The server (university) reports a password problem, but a reset doesn't solve the issue...

Andrew, in that case it should be impossible to connect with an other username and password either...