I grabbed the Self binaries and scripts a couple of days ago. I'm running it on a Sun SPARC IPC under SunOS 4.1.1. The very first problem I had is with getting _WriteSnapshot to write a complete snapshot (the system seems to work fairly well other than this). When I try to write the snapshot, it goes away for about 5 seconds, and then comes back with the fatal error message below. This sounds more
cannot write to file: Interrupted system call fatal error: write error
This is the infamous "SunOS 4.1.1 write bug"; basically, the write() system call violates its contract by returning with EINTR before it has written everything. This bug occurs in SunOS 4.1.1 only (not in 4.1). It doesn't always appear; writes over NFS normally seem to work, and writes to /tmp also work if you're running tmpfs. We got the bug only when writing to a local disk if I remember correctly.
A kernel patch to fix the write problem is available from Sun (bug ID 1052649). I forgot their 800 number, but your sysadmin should know.
Hope that helps,