What does Muxer BitRate too high really mean?

More insight into this:
I have just analyzed the VOB files using Mpeg Streamclip, and everything seems to be there (and the audio is in synch irrespective of whatever nonsense was showing on the DVDSP timeline- see lip synch thread). The weird part is that none of the jpegs show up- where they should be it just freezes the last frame of the previous clip until the next video clip shows up. So where are the images? The images are mostly used as chapter markers and buttons over video menus. Is this a clue to what the problem is?

Many thanks for your suggestions, Shawn. As this is a small project I am just using Compressor's "DVD PCM Audio" which produces a 48khz, 16bit, stereo, AIFF using the Uncompressed codec type. I know that audio can cause much more mayhem than it has any right to do, and on larger projects I always use AC3, but the weird part about this one is that I was able to build this project without issue until I tried to add subtitles. To test your theory I tried removing the audio from the troublesome clip, and got the same error.

I just compressed all the audio into AC3, which made no difference.

In my experience the actual bit rate has NO bearing on this error- hence the title of the thread. You might want to dismiss this as my own personal peccadillo, but I am using standard compressor presets, and have tried using the 120min one, which is presumably at a lower bitrate, and it has made no difference. The other reason for saying that it has nothing to do with bitrate is that I tried duplicating the final clip on the timeline, and it compressed the first one and then gave up at the end of the second one. IF it muxes the whole track, so that I can play it back in MPEG Streamclip, and the progress bar reaches 100%, but it just can't finalize the project, it must be something other than the bitrate of the video or audio, wouldn't you think? What is the issue with the jpeg at the end of the track?

Yes I have 4 subtitle tracks- one is buttons over video only, the others are the buttons and subtitles. No alternate angles or audio though.
So here is another test I just tried: I copied the final video clip and placed it after the last jpeg. It did exactly as before: built the whole thing and then gave up at the very end. This must mean that it can handle the bit rate of the clip, mustn't it? even with the extra burden of subtitles. It was able to build thw whole of the last clip, it did the freeze thing where the jpeg should be, it had all the video of the final clip, but it just wouldn't finalize. What goes on at the very end of the build process?

I have tried with and without the jpeg, and it makes no difference- it seems that whatever comes last is the stumbling block. the jpeg that I am trying to use has already been used before on the timeline, so is presumably OK. Is the fact that none of the jpgs show up in the VOB file significant?
I just tried deleting Par folder and built to a different drive just for good measure- no difference.

Regarding the buttons: I need the viewer to be able to use the buttons irrespective of which subtitle track they are using. I assume that that means that I need to copy the buttons to each track, as I assiume that I am right in thinking that only one subtitle track can be functional at a time.

OK here is the latest on this one, and I really hope that someone can shed some light in here.

I have used disk utility to repair all permissions.
I have tried deleting clips to isolate the problem, and it seems that it ALWAYS crashes or Muxer BitRate Too Highs me at the very end, irrespective of what the last clip might be.
Given that it is able to mux to the end- at least to the point that I can play the track in MPEG Stream and it all looks and sounds right- What does DVDSP do at the very end of a build? If I know what the final task is (ie after 100% complete and before the successful build message)I might be able to isolate the problem.
TIA
James

I am using DVDSP 3.0.2 on an IMac G5 1.8ghz running OSX 3.9

Interesting idea but no actual change. I deleted all the buttons as you suggested and it went to 100% and then crashed. I did notice in the log that it "prepares subtitles" before it starts muxing, so it is definitely something that has to be done at the very end of the process.

Nope- I deleted the preferences and that made no difference. I will try the seperate account next, but if anyone knows what the last action is in a build I would love to hear from you.

and trying it in a new account is exactly the same.