Unable to open file for reading

Hello everyone,
Lately I can’t author DVD’s with my IfoEdit, since it gives me the following message: “unable to open file for reading”.
This happens right at the beginning, when I try to start authoring after defining video and audio files to author (created with DVD2SVCD).
Any ideas regarding the nature of this problem? Tnx.

Most likely the DVD is copy protected, so you should just play it for a few seconds in PowerDVD, WinDVD, etc. to unlock it. (Just looking at that FBI warning screen should do the trick.)