|First, I don't mean to elaborate on the obvious, but I'm assuming you've loaded the korn shell on your R.H. Linux system.|
I'm also assuming you are executing the 3 lines in a script from cron? Executing .profile this way:
assumes cron the current working directory is the home directory. While it looks like it was true on AIX, but not on R.H.
Try changing to the user's home diretory before executing the .profile line.