UBB.threads PHP Forum Software Community Forums UBB.threads Installation and Upgrade Support Changed server name - now get error

You actually have the problem in bold:

Fatal error: Call to undefined function mysql_connect() in D:\Inetpub\wwwroot\ubb\libs\mysql.inc.php on line 44.

Basically that means that on the server you are now on, mysql_connect() isn't available to PHP. You'll need to check your php.ini file on the new server and make sure the mysql settings aren't commented out.