Registration inside FS02

Hey guys,Ive been browsing the forums, but unfortunately couldnt find any documentation to solve my problem. After recently purchasing the 737, downloading, and a brief installation process' I attempted to register my aircraft in Flightsimulator to encounter an error which says even with the pmdg 737 running: "Registration Menu Handler: you must have loaded a pmdg a/c to achieve the registration dialogue... please contact pmdg group support."I dont understand why it wont let me enter the code that I had purchased. Previous to this attempt i re-installed the aircraft after installing the microsoft gdi (windows me user).. Anyone know how to fix this?Thanks,Chris Smith