Comment 2 for bug 376932

Thanks for your bug report and for helping to improve Ubuntu. I was not able to reproduce this behavior. The Quicktime trailer you listed played fine for me and did not crash Firefox.

$ lsb_release -rd
Description: Ubuntu 9.04
Release: 9.04
$ apt-cache policy firefox
firefox:
  Installed: 3.0.10+nobinonly-0ubuntu0.9.04.1
  Candidate: 3.0.10+nobinonly-0ubuntu0.9.04.1
  Version table:
 *** 3.0.10+nobinonly-0ubuntu0.9.04.1 0
        500 http://us.archive.ubuntu.com jaunty-updates/main Packages
        500 http://security.ubuntu.com jaunty-security/main Packages
        100 /var/lib/dpkg/status
     3.0.8+nobinonly-0ubuntu3 0
        500 http://us.archive.ubuntu.com jaunty/main Packages

Perhaps it is not Firefox but your video driver or video settings?