I have uploaded TSLPatcher v1.2.8b2, which fixes a sneaky bug in the RIM handling class. Apparently the RIM specification I used contained incorrect information about where certain things were stored, causing the game to have trouble loading RIM files modified by the TSLPatcher (though KotorTool had no such problems loading the modified files).
This version fixes this problem, and the game can now load modified RIMs without problems as far as my testing shows. (Lesson learned: Don't rely on other tools rather than the game to verify that things load properly).
No other changes (that I can remember) in this version, the above bug was serious enough to get a version of its own. Still looking into the odd problems with recompiling scripts using multiple include files under some circumstances. Hopefully a fix for that will be made soon as well.