Go to Window explorer...
Tools --> Folder Options --> File Type.
Choose the FP7 and map it to your FMP9 application. ( Open with --> Browse )
Ah, Mr. Vodka, though I prefer gin, you are a man and a scholar. That was indeed what I needed to find out the problem. It turns out Windows is not recognizing Filemaker Pro 9 for some reason when trying to open files, although it work fine otherwise. Now if only I can get IT to actually fix the problem since they only give me power user rights...
Thanks for the help!