500 with simple syntax errors...

[eluser]Aken[/eluser]
Depending on how the server interprets a PHP install, a PHP error can throw a 500 error also. The 500 error states that it is not a client-side problem, which means it's something to do with the server set up and/or software, which can certainly include PHP.

I've personally never experienced a 500 error that resulted from poor PHP code, but I can see how certain set ups may cause it. MIne usually come from crappy .htaccess files.