I'm not sure if the movie folder is the problem, as I cannot play ANY GCM in Dolphin if it has been shrinked (...shrunk, shrunken, shrinkened, made smaller), I keep two copies of my GCMs one original size in a RAR (extracted if i want to play it) and one "made smaller" version to test with.
With the latest revelations of gCube i can deduct that "smaller" GCMs themselves are not corrupted (Well, a few i tested showed the openeing logos), its just seems that Dolphin hasn't got a 100% accurate disc reading plugin, which is understandable as it is only a Teaser (Please don't flame me, i was not complaining, just stating my diagnosis). I would try streaming to my cube to be 100% sure, but I can't find the effort yet as its not a major problem and i have the original discs!
Cheers,
Fox