zeropc said:

mkvtoolnix and subtitle editor don't like the provided .srt files

error message from mkvtoolnix

Error: '---' is neither a valid ISO639-2 nor a valid ISO639-1 code. See 'mkvmerge --list-languages' for a list of all languages and their respective ISO639-2 codes.

any ideas?

#update#

i run the subs i needed through jubler (open and then newly saved) and now mkvtoolnix has no problem with the remux.

The SRT files are just UTF-8-encoded text files with a byte-order mark--it's possible mkvtoolnix doesn't like that encoding (SRT files should not provide an ISO-639 code at all, so some very odd error is getting tripped there). If the Jubler processing is just stripping out the BOM or converting them to another Unicode format, that's probably fine, but if it's converting them to some 8-bit encoding, there may be some mangling with certain characters--check apostrophes and quotation marks for problems.

If mkvtoolnix supports BD-SUP files, you could use those from the project instead of the included SRT files.

EDIT: Verified that it seems mkvtoolnix supports BD-SUP files, so for those of you doing your own muxing, I'd recommend against using the SRT files and use the 720p SUP files from Project Threepio instead.