errors on Oracle 10g startup
 

I just installed, de-installed, and re-installed Oracle Database 10g R2 (that's probably silly, but I was getting errors and had no idea what else to do) on RHEL4u5. I used an installation guide I found here (and saw that the steps were similar to several other guides):
http://www.oracle-base.com/articles/...nRedHatAS4.php

But when I finished and tried to start things up, I got an error similar to the one that I got when I first installed 10g:
EM Configuration issue. /usr/local/oracle/product/10.2.0/db_1/[hostname]_oracledb not found.

The only error I got during installation was during database creation: "Invalid value null for parameter PORT" -- but I don't believe I was ever prompted for a port number, and this seems to affect more port values than just the database (EMD, etc.?).

Is this common for 10g installs Oracle on Linux? How do you fix it? Just running this command and entering a port for the listener did not work:
emca -config dbcontrol db -repos recreate

Thanks!