Apache won't restart after re-boot.?

How did you create the subdomain? At a guess, your change means it's now looking for fastcgi_params, which it didn't need before, and that's why it's throwing the error. A quick search indicates that the file is used for load balancing and there should be a sample/default file somewhere. I'd take this to the Apache forums - it should be pretty easy to find someone who can point you to the right directory or just send you a sample file.