Mysql errors

I'm getting these errors in my phpbb forum. According to phpbb, errors in line 48 are the hosts fault, so I'm posting here. And sometimes they come out and sometimes they don't.

Warning: mysql_connect(): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) in /usr/home/maku2adm/public_html/phpBB/db/mysql4.php on line 48

Warning: mysql_error(): supplied argument is not a valid MySQL-Link resource in /usr/home/maku2adm/public_html/phpBB/db/mysql4.php on line 330

Warning: mysql_errno(): supplied argument is not a valid MySQL-Link resource in /usr/home/maku2adm/public_html/phpBB/db/mysql4.php on line 331
phpBB : Critical Error

Could not connect to the database

http://bandoftheweek.com/community/index.php That's the url for the forum, it may not have errors, it happens like 50% of the time.