I have M8 V2.5.2 and I had the same problem when I updated quick time 7.1.5 The loops had a pause, so rolling back QuickTime my MacBook was very instable. I have had to reinstall Tiger

Now I have M8 V2.5.2 and QT 7.1.3 but It doesn't work well, my clips runs with a stutter

I downloaded JavaUpdate too.
Any suggestions?

Thanks a lot