It sounds very familiar to me if you are using fast file system, due to the 4gb limit. The last partition is ####ed because it spans above the 4gb limit. At least that is my guess.
There is an updated ffs where this should not be a problem, as well as other and (imo) better filesystems such as pfs or the one I am using that I forgot the name of, freeware, I think...sfs, it was. It rocks.
Still, at least sfs has some strange things you need to be aware of when going above the 4gb limit, but that is (or was when I installed it, at least) very well described in the docs.
Sincerely,
-Kenneth Straarup.
edit: hahahaha. I just noticed amiga.org automatically changes my cursing to #'s - and here I thought people was just mature enough not to write such words

edit2: the filesystems should be on aminet afaik.