Quicktime 7 In Tiger Does Not Play In Safari



I have recently upgraded to Tiger, but I have not been able to play any videos in Safari. I have tried to play some trailers in the apple quicktime website, but all i get is a blank screen where the video should be playing. This happened a while back while I was on Panther, but upgraded to QT 7. Everything worked fine when I used the QT 6.5 reinstaller. Is there something wrong with my system?

I am running a G4 dual 533 Mhz (digital audio) with 1GB RAM.

Thank you!