Version Conflict

Hi, I developed a CMS on my local computer (apache 2.x, mysql 4, php 4.1.2). it worked great, locally. As I loaded it onto my server ( apache 2.x, mysql 4, php 4.3.1) i had some kind of weird problems. Sometimes whem i click on links (going to my own site and always calling my index.php with parameters) it wont work. It shows "Page not found". When you have a local Webserver installed, it jumps to the root of the local webserver. I dont know how to fix the problem, cause it happens not every time. Sometimes it works sometimes not. I am nearly sure that it is a php-problem cause i tried it on an local php-server with 4.3.1 having the same problems... Does anybody know what could be wrong in my scripts??? Thx Max