User name null and socket default

[karthigeyan.nagaraja]

Hi
I installed mysql 4.1.11 in a linux workstation and started it new. I have 2 problems

1. socket defaults to /tmp/mysql.sock. <- How will I change the default socket to another directory where it actually resides.

2. When I enter in mysql, and do something the user name is forgotten and hence I get this error message.
(I tried with both --user option and without it.)

Access denied for user ''@'localhost' to database 'mysql'

When I work as a root user there is no problem.