There are a few things that can cause this error. You said your HD space was disappearing, lets start there and see how much space you have left.
If you are root on the machine or know for a fact you don't have a quota: df -h
If you have a shell and have a quota, contact your provider about how to check your free space.
The reason this is important is that *nix systems see everything as files. Sockets, file descriptors, everything and if you are at your quota then you can't create new sockets(files).
It's also a good idea to insure Anope isn't already running.