Well, me and your server sat down and had a lovely conversation.
Apparantly, your server is sitting there wondering what you are thinking expecting your PHP scripts to just mosey on over from PHP3 to PHP/4.0b2
Cause here's what your server said:
HTTP/1.1 200 OK
Date: Wed, 17 Apr 2002 07:36:50 GMT
Server: Apache/1.3.1.1 SSL/1.15 PHP/4.0b2
Transfer-Encoding: chunked
Content-Type: text/html
Do some digging around in the scripts to see what functions/globals you may be using that are depricated/removed from PHP4.0