A couple of suggestions for you. I know you said you already tried some of this, so sorry if some of what I'm going to say is a repeat, but go through these steps again.
First, remove any /bin/bash or /bin/sh from the start of the ProgramArguments array in your plist. As long as your script is executable, those aren't needed (see next point)
Second, check the permissions on the script to ensure it is executable. A simple way to ensure this is to run sudo chmod +x /Library/Application\ Support/company/Tools/RefreshKerborosTicket.sh against it in Terminal.
Next, you might want to choose between having the StartInterval in your LaunchAgent job at 10 seconds, OR using the WatchPaths. The Watch Paths are designed to trigger the launchd job into action when changes are detected in any of the files or paths in that array. But a launchd job can ONLY run at most every 10 seconds. The OS will throttle anything trying to run sooner than that. In fact, if you use WatchPaths, I recommend including a ThrottleInterval added with an integer value of 10 seconds. But if you have a StartInterval set to 10 seconds, that's really all you'd need, though I would argue for something like a script checking/renewing Kerberos tickets that's a bit extreme. There's no need to have it run quite that often in my opinion. Bumping it out to every 60 seconds would be more than sufficient it seems.
Lastly, in terms of the script itself, which script are you using from the thread you linked to? Can you post the script here, sanitized if needed? It's possible there is something in the script it's attempting to do that's throwing the error.
