You must be using BGTutu or BG Trilogy . I've just checked the item's file, and the proficiency (used by the BG2 engine) wasn't correctly set! I found the same problem in case of Club +1. I've fixed both of the items, and I'll include them in the next release of the mod (which won't happen too soon, probably).
Thank you for reporting this very important bug!
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I just finished the mod. I was wonderful. Kudos to all who had a hand in it.
Glad to hear you liked it. While spending my holiday skiing, I managed to work on Episode II: Black Supersitions, so the hope to release it before 2007 might not have to be forgotten.