I believe you are using a password, and you are running on Windows Vista. Vista likes to ask you for your password multiple times (You never can be too safe, says Vista), and also likes to prepend some garbage at the beginning of your username, but only on one of those times. When that happens, just edit the user name.
So now, you can resolve the issue by selecting the "Connect as different user" option with the Map Network Drive dialogue.
If this doesn't work, please visit our support forums at
http://www.avatron.com/support