If you have set up Oracle as per the instructions (look at Andrew Piskorski's one for example, his instructions are excellent!) then you should have configured the listener to start on boot up, right? Make sure the listener is running... in redhat you could do something like (if your startup script is called listener8i for example):
/etc/rc.d/init.d/listener8i start
Another way to see if those ports are being
binded is to do something like:
netstat -an
Again I know it works on Linux/MacOS X, don't know about other OS, and look for those ports you mention.
Just my 2 cents
