iMovie won't import gameplay files from Elgato.

I recently got an HDPVR (The Elgato Game Capture HD) to record gameplay from my Xbox 360. I recorded about an hour of gameplay and used the Elgato's software to import the file into iMovie. It began it's import but got hung up on a part that said "Generating thumbnails." It would say that it would take about a minute but this estimate would climb until it said "about an hour." I've left it overnight and still no import. I tried to close out iMovie (eventually having to force quit it) and start again but now everytime I reopen it, it returns to that same point, refusing to continue on and I have to force quit out of it everytime. Any suggestions on how to fix this problem? Please help.