232805 cross browser compat. issues

Hi, I had a website put together and I like it but I need the code cleaned up. The main issue is I have a script called PHP Motion installed and it is not working in Internet Explorer but it works in all other browsers. I have been told its because the code is not browser compatible. I tried to get my designer to change it but some reason he doesn't think its necessary. I'm just anal about what I want so I was hoping someone could help me. It's probably a quick fix too. Please make an offer because I'm not sure how much things like this cost or the time involved in analyzing the code. Please contact me for more details.