Using Mac OS 8.0 or Mac OS 8.1 with QuickTime 2.5 installed, QuickTime movies may not play back correctly or may cause the computer to stop responding when played from an ISO-9660 CD. If the movies are dragged to the hard drive first, they work correctly.
If the movies are played from a standard Macintosh format CD, they work correctly. Using system software 7.6.1 or earlier, the problem doesn't occur.
This issue was fixed in QuickTime 3. The latest version of QuickTime can be downloaded from Apple's web site:
http://www.apple.com/quicktime/