I just spent the last few days trying to get a demo for work to work. We had a similar demo last year but for some reason when I tried to port it over to a newer platform it wasn't working.
I did everything to debug it. I tried installing older versions of the program, combing through it and every related programs' configuration file, and actually looking at the code. None of this was successful.
Than, by chance, I found a small post on a message board that told me exactly what was wrong It ends up being that in the version of Linux I was using, Fedora Core 3, a new feature was added that basically stops programs from being able to execute certain commands. By simply changing ONE WORD in a configuration file from "enforcing" to "disabled" fixed the whole thing.
3 days - One Word. I was overjoyed that I found my problem but still so angry that it was all caused by a single solitary word. Got to love technology.