I don't speak for PTC, but I would caution you that parallel port dongles are somewhat more sensitive and finicky than USB dongles.
Apparently it is possible to damage them by plugging or unplugging them with the computer powered up. I recall seeing these warnings when we had parallel dongles for another CAD package back in 2001 or so. Out of ten parallel dongles, 4 of ours died for unknown reasons.
Also, you may want to make sure your parallel port is enabled in the computer's BIOS, and that it is listed in the Windows XP device manager. I don't recall if these require bidirectional ports, but that could also be a problem. (PS/2 / ECP / EPP)