Warning: mysql_connect() [function.mysql-connect]: Access denied for user ‘IUSR’@’localhost’ (using password: NO)

If you keep getting this warning, even though you are supplying a different username and a password, make sure the sql.safemode setting is Off on the php.ini file. On linux/cpanel instead of showing IUSR the user of your cpanel account may appear, but the problem is still the same.