I run slime on Gentoo, but I don't use the Gentoo port. Try installing slime out of CVS directly. Then it creates the ~/.slime directory like its supposed to and everything works.
--Jeff Cunningham
Thanks for the reply, Jeff. Actually, I did try that. However, it also did not work for the same reason. That is, the CVS version of slime had exactly the same problem. It did not create the ~/.slime dir.
The problem has ceased since I unmerged slime, ran the "rm" command to empty the cache, and then re-emerged slime. Now the REPL comes up normally using the Gentoo port. For how long? Don't know.