[X4U] When passwords aren't accepted

[n]

I'm having problem with a powerbook (Panther install) on which I can't 
log onto another mac, which I've logged onto before.

Keeps telling me my password is incorrect.

Now, anybody can hit a wrong key, or type too fast, but after 10 times 
or more, *painstakingly* entering each character with the utmost care 
possible, I know that I typed in the correct username and password, and 
still was denied. Restarting the macs and trying again didn't help.

Now, for some apps, when incorrect behavior happens, I know to trash 
the prefs and try again, but for this, I don't know if there are prefs 
or some file which may go bad and needs to be trashed.

Anyone know if there is such a file and how I might tackle this issue?

thank you!

n