Originally Posted by Lord Of Light
Navigator still pops up but if I close the terminal Navigator shuts down too.
I don't know about the error message, but it is normal for the program to shut down when you close the terminal. If you don't want that to happen, then you need to put the command in the "background" by following the command with an ampersand. And if you do that, you probably want to redirect STDOUT and STDERR some place. If you want to background the process and just throw away all output, then:
./navigator > /dev/null 2>&1 &
All of this can be avoided if you just start the program from a menu, an icon, or the "run" command, which is how programs are usually started in a GUI.
EDIT: I left out a step for making the program persist after the terminal is closed ... You also need to tell the shell (terminal) to "disown" the process. You can combine both of these into one step:
./navigator > /dev/null 2>&1 & disown $!
In this case the ampersand both backgrounds the process and separates the commands. "$!" just refers to the last process that was backgrounded. If this seems overwhelming, just "cookbook" for now and hopefully, in time you will come to understand it.