John,
I'm guessing your output looks something like this?
X-Powered-By: PHP/4.0.1pl2 Content-type: text/html
If this is the case, the problem is caused by having dynamic extensions uncommented (ie. loaded into the engine) in your php.ini. Just comment out all the dynamic extensions and see if that solves your problem. It won't affect MySQL as support is now native. For additional dynamic extension support, try going to either:
1) download.swwwing.com
2) www.mm4.de/andreas.otto/php_related/
Both sites have provide PHP builds with additional support. Hope this helps!
Cheers,
Geoff