The availablility of force heal is there as it is the only way to add the mission briefing into the datapad. Just pretend it's not there - only a couple of other people discovered this
The other problems you are experiencing I have never heard of! No-one has ever had problems like those!
I run JKII (and the MOD) using a GeForce 3 - I've seen it with my own eyes on a GeForce 4 system. By reading what you've just put, I highly doubt the video card is the cause of the problems.
Are you running the MOD in the "base" directory?
If so, create a folder called "dark" in your "GameData" directory and then run the MOD from the MODs menu in JKII SP.
Do you have any other MODs installed (in your base directory)? There have been conflicts before.
Other than that, make sure you have JKII version 1.03 or above. Check the latest graphics card drivers etc..
If you are still experiencing problems after having checked out all of the above, then head back here and we'll try again!
Glad to hear you enjoyed the demo