need mysql php error fixed

i am getting an error shown in my error log repeatedly - the pages load fine but i'd like the errors fixed and hopefully the caching to still work it has to do with caching i have setup in [login to view URL] the errors are PHP Warning: mysql_errno(): supplied argument is not a valid MySQL-Link resource in /home/katiehau/public_html/db/[login to view URL] on line 408, referer: [login to view URL] PHP Warning: mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Can't connect to local MySQL server through socket '/var/lib/mysql/[login to view URL]' (11) in /home/katiehau/public_html/db/[login to view URL] on line 51, referer: [login to view URL] PHP Warning: mysql_errno(): supplied argument is not a valid MySQL-Link resource in /home/katiehau/public_html/db/[login to view URL] on line 408, referer: [login to view URL] also i am using mysql5 not 4 so im not sure if this file should be edited for that i have attached the [login to view URL] file ## Deliverables here is the file