I have a DVD9 with badly sync'd audio on one track - about 15 seconds off! (It's a bootleg with multiple language audio tracks.)

I am very new to messing with the guts of DVD's, even though I have been doing my own brand of all-purpose video and audio work for a long time, so please keep that in mind.

What I have done so far is,
1) demuxed with PGCDemux
2) stripped the AAC audio and fixed the desync with Delaycut
3) remuxed with Muxman
4) inserted the repaired VOB's and IFO's back into the original DVD structure, by following the VOB Blanker guide availible in its HELP menu "Adding Back Original Menus to a
Re-authored DVD with PgcEdit and VobBlanker".

When I then go to rebuild the ISO, ImgBurn tells me there are "no cells available for creating the layer break".

If I build the DVD9 anyway, I get a working image, with all menus, etc, and my audio is functioning and sync'd! But, I'm unable to burn this rebuild DVD to a dual-layer.

Where in this chain of events could I do something differently to save the integrity of the layer break? Or how could I create a new one?