Is it possible that you have “the copy protection” on? I had problems with the error message (something like this) “This image has sector headers and needs to be removed, remove and continoue” after my update, so I was pushing yes, and the dvd was burnt as if nothing happend. This turned out to be a problem. The dvd’s did not work with “winplayer” or on any apple computers, ohps problem! Anyway – I learnt that this was the copyprotection that needed to be turned off, but they were already off!?! Yes they were, acctually they were never turnet on from the beginning. So I had to turn “eveything on” save a projekt. Then restart my pc, open the project I just saved, turn “every thing off” again – save as… to a new folder – reboot my pc… and it is magic – it is solved. I have no more problems, it playes in “winplayer” and on my ibook again.
But some of my old projects still has this problem – then I “just” 😉 do the same precedeur again. I don’t know if this is your problem, if not…Zzzzz 😉