Authenticating Jaguar SMB from Windows
MacWindows.com: Mac OS X 10.2 (Jaguar) Cross-Platform Issues
I'm guessing the problem is it needs to make the password hash for Windows Kerebos authentication and it can't do that because it doesn't have your plaintext password. Apple could have avoided that problem by prompting you for your password when you enabled the "log in from Windows" checkbox in your user account preferences.
Oh well, at least there's an easy fix!