Quicktime major problems

I was going to watch the new iLife 08 guided tour from Apple's website. I have the latest quicktime version, latest updates on all software.

Windows:
Firefox 1.5: The quicktime video will crash firefox, or firefox will say that the quicktime plugin did an illegal operation. If it doesn't, it flickers and sometimes the video is completely garbled.
IE7: Same thing, dll crash.

I tried uninstalling and reinstalling quicktime, no difference.

Mac OS:
Firefox 2.0: The quicktime video will flicker like crazy, and the system becomes sluggish (as if firefox/quicktime hogging CPU cycles).
Safari 2.0: surprise surprise, no video problem. The quicktime video runs just fine.

Gee, wonder what's going on. Does Apple do something specific on those videos so they only play nice with safari? The only workaround in windows is to set quicktime to safe mode (GDI). I haven't found any workaround for the flickering videos and sluggishness in the Mac firefox yet, other than to use Safari.