I've found that I cannot run a script defined to the PATH environment variable. For the given slave-node, we set PATH in the slave-node configuration. We have a specific script (qt48-run) which is a wrapper-script, to add certain elements to the PATH and LD_LIBRARY_PATH. The wrapper-script resides in a directory we define to the slave-node-PATH. We cannot run that wrapper script.

To illustrate, we made a job that just runs "printenv PATH"

Execute Shell: printenv PATH
Execute Shell: qt48-run printenv PATH
Execute Shell: echo -------------------------------
Invoke XShell command: printenv PATH
Invoke XShell command: qt48-run printenv PATH

The resulting console output (with stack-trace) is attached. The xshell plugin just simply does not find the specific "qt48-run" wrapper script. In our case, that script resides at /usr/devtools/linux-environments/.

... by the way, the xshell documentation does say that a script can be run from the PATH, and not necessarily in the local directory.