Going by a few things youve posted in the last few days it really sounds as if your os3.9 install is pretty screwed up.
Installer should be part of th default install for example, as is unarc (which will deal with lha files "out of the box" when you double click on them).
Being that I dont use ClassicWB I cant be sure, but it sounds like youre asking for trouble by overwriting/supplimenting your OS3.9 setup with classicwb in such a way.
