mysql : cannot login with other users than root

[george roman <g@camin9tm.afraid.org>]

hi, i have some troubles with my mysql-server. i cannot login with other 
users than root. this is the error

camin9:/home/george# mysql -u dan -p
Enter password:
ERROR 1045: Access denied for user: 'dan@localhost' (Using password: YES)

i've try to add this user with phpMyAdmin and also from command line 
from mysql.

with the root user i connect with success and i can make anny command.
i gues the problem resides on a file permision for reading or somethinf. 
but at the moment i do not know where should i look

please help.

PS this is the only normal user i have on my server.
i use debian woody