Should I try to re-install BGT-WeiDU, then? Is there a problem if I run the setup again?
I honestly don't know what went wrong. The log showed nothing of interest (by which I mean just 10 lines of unimportant information). It's obviously not fully installed, since it's supposed to copy the entire BG1 installation into your BG2 installation, so it should take at least a minute or two. So... try it again and see if it behaves differently this time.
I tried, and the same thing happened, a window opens, and a few seconds later, it closes. What should I do? This doesn't make much sense...