bob,
I've had reports of that in the past... I was able to reproduce it once, but not consistently.
Try downloading a different version from my cable modem:
http://amped.dnsalias.com:8000/Oasis-4.5c.zip
(Checksum: a87b91360e3d7c15b8fdbb09bf991852 Oasis-4.5c.zip)
You should be set with that. I'll forewarn you that in one of the versions (can't remember which) postgresql wasn't starting on boot. To make sure it's up and running, just type
/sbin/service/postgresql start
After that you should have a working OpenACS system to play with.
