A bug has been found where the user manually edits the run path in a workflow and makes it invalid...

The problem is that the command that should run does not run and we show
an error message saying that the command could not be found when it fact
it was an invalid run path... A hacky way of catching this kind of
errors has been implemented, but it wold be better to be able to show an
error message in the log window instead of only in the status bar.