Starting Domino 5.0.11 crashes system!

Folks:

I'm a total Domino neophyte ... I'm trying to install & start a simple
Domino server so we can test some integration with a product.

Friday I installed & configured a Domino 5.0.0 server (yes, I know it's very
old) ... and, when I tried to start the server, the AS/400 crashed (running
V4R5).  There didn't appear to be an SRC code on the front panel.  The
system dumped upon re-ipl.

I uninstalled Domino 5.0.0 and installed 5.0.11, configured a server, and
tried to start it up.  Once again, the system crashed.  I'm not in the
office right now, so I can't tell if there is a SRC code or not ... but I
suspect not.  The system is pingable, but I can't logon (telnet or
passthru).

I tried searching the AS400 knowledge base & notes.net documents, but
couldn't refine the search enough.

We've called IBM for the first crash, but haven't heard back yet.

Any suggestions on where to start looking?  Am I missing a critical PTF?

Thanks!

david