Jume

uh, to tell you the truth, i didnt noticed the words "quicktime movies"
::embarrassed::

maybe only one of these were making trouble, if you need to see .mov files
(which i think you need or you wouldnt have this problem) try installing
only one of those and check if the problem reappears, if it does, uninstall
and try the another

just be sure to download the very latest versions

good luck!