Often I have a script that works great on the command line, but fails when run from FastScripts. Its usually related to differences in the environment or forgetting to add the executable bit to a script file.
What's the best way to debug things like this? In Ruby scripts, I was using rb-appscript with the Standard Scripting Addition to display dialogs to sprinkle in logging, but it's a painful experience. It'd be really great to get the error output directly.