[PHP] HTTP 500 server error

[Web user]

It always gets HTTP 500 server error, when I  try to run the php scripts on Windows98 
SE + PWS4.0. 
THE PHP installed is Ver 4.06 -win32, as a server module.

However I get a screen full of html codes when  I run c:\php\php.exe -i in MS-DOS 
command line

So what's problem with the installation or configuration?
Thanks

BAKER