You will need to look at what actually happens. What the output of `env` is, also the error output. And of course, also what happens in your login/profile scripts. Most likely one of the scripts is not run when no terminal is connected. Adding set -x to the top of all interesting shell scripts will provide lots of informative output of what gets run when. Also, manually logging in as a different user, preferrably with an empty environment, and then running the scripts of your user might prove helpful.