This is usually the result of a shell LANG environment that is incompatible with IDL and/or IDL Online Help. Presumably this can be solved by changing the LANG setting of the shell that is set to spawn 'idl' or 'idlde'. Here are three steps you can take: 1) "echo $LANG" should show the current "language locale" setting of your Xterm. I am guessing your call will return "C". 2) The UNIX shell command "locale -a" should reveal all the LANG settings that your operating system can accept. You will want to choose only from this list when you do the next step. 3) In a C-shell enter: "setenv LANG en_US.UTF-8" ... Alternatively, in a 'bash' shell enter: "export LANG=en_US.UTF-8" ... ... before you call "idl" or "idlde".'en_US.UTF-8' is what is working (with newer IDL versions, anyway) on my own UNIX shell. I do not know if it is a good choice for IDL 5.5. You could try other 'en_US...' options that were shown in your "locale -a" list. I believe there was also a time when the LANG=POSIX setting was compatible ... and it may still be. Anyhow, you may have to experiment. Good luck with this old IDL. My first recommendation should probably be: "Upgrade!" James Jones