If your session fails to start with Server configuration error and the system log on server side, usually /var/log/messages, reports an error similar to:
 
 NXSERVER 2.1.0-22[16670]: ERROR: Found error while parsing line:
 '/usr/NX/bin/nxssh: error while loading shared libraries:
 libXcomp.so.x: cannot open shared object file: No such file or directory
 
it is likely that your NX Client installation is corrupted and the libXcomp.so.x.x.x  library, which is shipped by the client package, is missing. Reinstalling NX client may solve the problem.

If your session fails to start with error:
 
NX> 596 Error: Unexpected termination of nxagent process.
 
and the session log on server side reports an error similar to:
 
 /usr/NX/bin/nxagent: error while loading shared libraries:
 libXcompext.so.x: cannot open shared object file: No such file or directory
 
 you may try to reinstall either NX Client and NX Node.