Hey "M", you must pay attention to the direction of your slashes also.. for example, they should be like this:

C:/Program Files/AliasWavefront/Maya4.5/scripts/GIJoe.lights

NOT like this:

C:\Program Files\AliasWavefront\Maya4.5\scripts\GIJoe.lights

It took me a while to figure that out, but I got it to work eventually