I have java 1.4.2 or higher defined in my .cshrc (.bashrc) file but the GUI doesn’t recognize it.

1) Look for the following line in your .cshrc (.bashrc) file:
     source ~ Epos3_env
     This will override the java that you have set as $JAVA_HOME and use the java for Paradigm /      Geodepth.

2) Some versions of Linux OS have a place holder for java. To override this, put your      $JAVA_HOME/bin path first in your $PATH definition in your .cshrc/.bashrc file.

My node.db file won’t display in the Node Selection window of GUI.

Check that there are no hidden characters in your node.db file with a text editor. If your node.db file was created on a pc , you may need to use the dos2unix command on the file.

I keep getting the following error: OS Error: could not map rld from file /lib32/rld

1) There are not enough file descriptors available. To resolve this issue:
     a) in csh, do following command: limit descriptors 500
         verify with: limit
     b) in bash, do following command: ulimit –n 500
         verify with: ulimit –a

How do I set up rsh for my system?

http://evuraan.blogspot.com/2005/02/how-to-turn-on-rsh-and-rlogin-on.html
will help you get started.

I’ve issued the start command from the GUI but the job doesn’t run

Things to check:

1) Test rsh: rsh node_name date

2) Test rcp: rcp some_file node_name: /tmp

3) Check xterm where GUI was launched to see command that was issued.
     If you see “null” in the command line, there may be a typo in your node.db file, hidden characters      or some other issue with the node names.

4) Make sure you have the correct node.db file set in your parameter file.

5) Node names must be in sync. Check /etc to make sure names are correct.