.tbg files with DLTCEP

Hi,

I love the old custom stuff from places like Arundor's Abode, BG Storeroom, and Dharlome's Keep. Weird thing is - I can only import BG2 stuff from Arundor's Abode. None of the BG1 stuff will import. I get an error message from DLTCEP saying it "doesn't support this feature". Any thoughts?