I have exactly the same issue with VCD and SVCD File playback (I copied avseq01.dat to harddisk and tried to play it there). Same error-messages, same behavior. I was also able to play it before (last time i tried an svcd was about a month ago, so on my side something could have been changed - I'm not sure)
... what's really strange is, that MediaPortal is crashed fully, when I try to play the files directly from CD. - even with Task Manager it's not possible to shut down MP any more.