New to this forum, and pretty new to Blu-ray authoring, so I'll start from the top

I'm working with Scenarist BD and have a 6hr program with French and English subtitles. This is a menued project - buttons to play either the English or French stream.
I've successfully completed previous projects in a similar fashion, but none that were 6hrs in length (or dual layer) and have been having a terrible time trying to figure out the layer break. I've been using the "Disc Layout" tool. I've tried auto layer break, only to get an error when muxing. I've tried manual, but I still get this error: Allocatation Fail --- PTS LayerBreak: Specified PTS is not in the range of Clip.

Since this, I've realized that the auto layer break was on a chapter point, and I've been manually trying to move to a point that this error doesn't occur. I've even done test muxing - once without the subtitles and it went smoothly. As soon as I add the subs back on I get the same error. I've also tried to manually create the PTS break where a subtitle doesn't occur and still, the same error.

Can anyone help?! This is kinda urgent (of course).

THANKS!