A few pointers and a few questions :
Do you have a regular user account?
You seem to be logged in as root all the time.
When you're root, you don't have to do "su"
"su" stands for either switch user or superuser and is used to switch from your regular account to the root account.
[root@x1-6-00-0b-06-5e-48-3f root]# # rpm -ivh j2reversionnumber -fcs -linux -1586.rpm
The # indicates you're operating as root, you don't have to type it.
Did you actually type "j2reversionnumber -fcs -linux -1586.rpm"?
You have to replace the "revisionnumber" part with the actual revision number from the java runtime.
And you have to issue the rpm command from the directory where you saved the rpm file, navigate to it using cd followed by the name of the dir where you have to go.
Spaces man, spaces this would be
# rpm -ivh j2re-1_4_1_02-linux-i586-rpm
And please edit your post to remove your root password, you never know who can brwose through these forums.
Don't know for sure if someone would be able to do something with it but better safe than sorry.
That would count for always being logged as root too!!!
If you have a user account, use it, switch to root (su) whenever you need.