I have been playing with ToEE CO8 New Content mod for a couple weeks now and thought I'd check out KoTB. I followed the link on the main Co8 forums page "Download Now" and downloaded it from ModDB. I installed it here: C:\GOG Games Modded\Temple of Elemental Evil When it was installing I got an error message. I tried to do a Print Screen, but had the F Lock so it didn't catch it. It was something about an error when trying to delete a file called "DeleteFiles" or some such. Selected Ignore when I encountered this error, let the installation continue, it launched itself when it was done and TFE-X locked up then eventually crashed (I left it for about 5 minutes while I took my dog out). Next I launched TFE-X and if memory serves I had to Activate KoTB. Next I hit Play, and it is obviously a different theme music and the panning main screen is distinct from ToEE. But game locks up and is unresponsive after about 5 or 10 seconds (before the black background has fully panned off to the left). Music continues but nothing else. Let me know I an uninstall, reinstall and try to replicate the error and post the screen cap if you want.
Try toggling your settings for movies (turn off or on depending on what you currently have). People have reported this a few times as helping if they get problems when moving from KotB to ToEE or vice versa. Otherwise a reinstall may be necessary.