Ok, the only bug I’ve found so far with iDVD ’09 is that for long scrolling credits, it seems to have a memory pointer problem and creates hash for the scrolling credits. I’m guessing that this is because scrolling over an image is really hard on the encoder. It works fine from iMovie ’09, but whne iDVD tries to make a DVD (technically, it is transcoding from H.264 that iDVD produces to MPEG-2 that DVDs use).
So beware. I fixed this by making the scrolling no longer than 45 seconds that seems to work.