Help with Mac OS X (host system type... PowerPC-Apple-Rhapsody5.3)

Hello.. I'm trying to install PostgreSQL on a server and I'm getting the
error

"PostgreSQL has apparently not been ported to your platform yet..."

I was hoping for some help with the possibility of a manual
configuration I would assume that I can use the Linux one as OS X
supposedly is compatible... But this version is the original release and
has never been updated (and they people I'm working for don't want to
update it).

Thanks in advance.

Mark Irwin