I have this same problem randomly as well as other bugs with CS4. I have lost a lot of productivity time screwing with work arounds, re-installs, etc. CS3 was great, but if Adobe can’t do any better than CS4, why should I upgrade to CS5? Adobe will launch a CS, upgrade once or twice and then if any bugs are still in the software, you have to pay for the next CS. With the amount of time I have lost with CS4, they should hand over CS5 for free. I like my PC so FCP isn’t an option. May need to look into good old AVID…