I installed Yabb here (On a 100WebSpace hosted site) last year to test out for a friend and it seems to work fine without a hitch. I think it may be important to use a good FTP program to upload the files. I used "FTP commander" (For Windows. "free for personal, educational and non-commercial use" ). I'm not sure how good it is (the FTP program) generally speaking, it was the first time I used it but it worked. (The Yabb redme instructions include a warning in regard to some other lightweight FTP program I was using previously so I downloaded something else which happened to be FTP commander) I just unzipped the Yabb files locally to a directory and uploaded. Used the installation program (included that runs on the server after uploading it) and otherwise just followed the instructions provided in the "readme" files..
I installed Yabb - just as an experiment, or "educational exercise", at someone else's request (who, at the time was intereted in running a BB then moved on to other things) and haven't really used the BB site, but when testing it, everything seemed to be working perfectly.
I discovered that I love Yabb, BTW and do intend using it in the future once I get a permanent site set up for it. The test forum is still up and running...
http://mygeneration.farvista.net/yabb2/YaBB.pl
Proof that at least this version of Yabb (That can be unzipped on a windows machine with a built in installer that is uploaded and run on the server) does work on 100WebSpace at least. Lots of cool features, though figuring them all out and administering the BB takes some patience and persistence.
As this (the above link to the BB) is just a test forum that will probably be taken down or moved or something eventually, feel free to sign in log on/explore try out or whatever. (If it hasen't already been moved by the time anyone reads this)