A driver is the software that makes printers, cameras and other peripheral equipment work within the Operating System. When you buy these items they come with an installation disk. On that disk are the drivers. Running the disk installs a 'driver' for the equipment.
Drivers are written by manufacturers to work on specific Operating Systems. Your JamCam installation disk seems not contain a driver (software) that is designed work with Windows XP. Neither does XP have a driver in it's own library that it can use. When this happens the operating system is said to 'not support' a piece of equipment.
Mostly, if the equipment is not too old, manufacturers write new drivers for any Operating Systems that come out. However, in the case of your JamCam they've gone out of business before making one readily available for XP. Luckily some great people on the Internet don't accept this situation and set about either tracking a driver down that will work, or writing a driver themselves that will do the job.
So that is what drivers are all about.
I also came across
this site that might help you.