fatal: cache id 30 (or alike)

Following belows thread

http://www.mail-archive.com/pgsql-hackers(at)postgresql(dot)org/msg43381.html

I am experiencing the same problem on a brand new, extremely fresh, solaris 5.9 and PostgreSQL 7.4.6 box.

As expected, the problem was solved when passing the -d [1-5] to the postmaster. But... I was wondering (after googling and founding less than 1 page of posts related) if a diff was submited in order to avoid some strange debuging mesages when using the psql :)

OUch...also using GIS, but I don't believe this has something to do.

If needed, I would post the output messages, but thought that the above link will (exactly the same messages) provide an idea.

Hints?

Thanks in advance,
Guido