We have two sites for one of our biggest clients that have recently started giving us trouble. All of the sudden, on only certain computers, the video files have stopped playing but the audio is just fine. A few people at my shop have recently upgraded t heir Macs to Leopard so at first I thought it was an OSX problem. However, some of the Leopard machines operate fine while others do not. I assumed that the flash components on these computers must not jive for some reason so I upgraded the players to Flash 9. Still the same problem. It seems so intermittent. Here are the link to the two sites. Just click any of the buttons to transfer to a video page. PLEASE FELLOW BOVINES HELP!!!!!
I'm not sure, I haven't read any articles to that effect, and I doubt Adobe would let such a bug slip past it's beta team. The new Flash Player however, does mean a big change in how Flash handles video, since it introduces HD capabilities.
The reason I suspect Sorensen Spark is that it is a slightly outdated codec and I, along with many others, generally prefer the On2 codec. Furthermore, the symptoms you describe are generally credited to faulty codecs.
So my advice is, try encoding one of the Quicktime movies using Flash's Video Encoder with On2 VP6 codec and see if that works.