[kh99]

As a couple of people have mentioned, you should make sure your config.php is OK by starting with a fresh copy (or the one from the old server) and using a programming editor to make changes (you say you didn't chnage any of the files, but wouldn't you have to change config.php if you moved servers?). The reason the original error says "unable to add cookies" is because they cannot be added to the header once any output has been sent, and the hidden character at the beginning of config.php causes output (this is a common error message that's been seen here many times, that's why everyone's so sure what the problem is). How did you manage to change the cookie prefix if you were getting that error?

I don't know what's causing that other error - which version of vbulletin are you running?