stupid question - have you tried importing the "2nd" concert into TMPG DVD Author *first*? if it imports fine, then i'd say the issue is with TMPG not wanting multiple video files on the same disc... and in which case, maybe there's a "trick" to getting TMPG to accept it, and maybe there isn't a trick.

it's times like those that make me really enjoy a good authoring software... like one that can trim the video (without re-encoding), put multiple videos on the same timeline (again, without re-encoding) and create a sync'd audio track for the multiple video files (again, no encoding, only sewing the audio tracks together as a larger file). mmm, good stuff when you need it!

btw, silentmachine, you are aware of DVDDecrypter and/or SmartRipper, correct? you can do the ripping/demuxing in *one* step (by having either of said programs rip the DVD in Stream processing mode). if not, you should check it out. both of those programs are freeware (magic word).