well i got some good news and some bad ones.
The good one: The script is ok.
The bad one: The problem is the OS or Indesign or FontManagent.
Make sure you have the fonts properly installed on your sistem before running the script (starting indesign AFTER the fonts have been installed might help also). If you are using Extensis Suitcase for font management.. well i'm tempted to say uninstall it, throw away the installation CD etc, but i know it's usefull form time to time, so.. just make sure all the neded fonts are activated, and try again.