I have the same problem as Arlaya and when I put an empty baldur.bcs in the folder it indeed runs without lags, but do I want the extra's of the mods I installed.
Killing everybody, throwing away bags of holding (or all items) does not solve the problem. From the previous discussion it seems that cleaning up the baldur.bcs file is the solution but where do I find it and what can I delete from it because it is not in the override folder after installing the mods? (and I doubt the baldur.bcs file in the Bg2-SOA\SOS\over.bak\baldur.bcs is the right one)
I included the WeiDU.log file.