Why does my new windshield leak?

[cwilkie]

I purchased a new windshield, weather stripping, and windshield trim. After getting it installed it leaks in a few places. Before it was the original glass and weather stripping without the trim. Is there a trick to getting the glass installed properly? Is there higher quality weather stripping out there? Or do I need to not use the trim? Please let me know what you guys think because every time it rains I get water all over my new interior.