PHP puking as a server side include?

I was wondering if anyone has any idea of what would cause the rather obvious error on my web page, . The two portions on there are both server side includes of the same script, the difference being that the one on the left doesn’t have anything before the first PHP statement, and that the one on the right has a space at the very beginning of the file. Now, the solution there would be pretty obvious, but adding that extra space in there pushes the first line down a line, which ends up throwing off my formatting severely, so I’d prefer to actually have things working right.
If it matters, I’m running PHP as CGI, and not running under PHP5 (I’ve tried changing both, and neither have solved it).
Thanks in advance for any help!