Looks like I've run into the same problems as yourself when trying to get example 11.2 to work. I keep getting an Apache 404 error when I try to follow one of the links generated by the script on a previous call. Looks like Apache checks for existence of document before calling the "query_track.cgi" script - which is never going to exist because it includes the "extra path information"!. I wonder whether you experienced the same and got around it??

Regards

jim