Backseat Install

I don't remember the bolts being anything other than ordinary length there. Does the bracket not flex downward enough to get a bolt in there? Could be that you're not hooked in all the way up top but I'm guessing you would have realized that if the top of your seat was a few inches higher than the package tray.

I'd try removing the seat, inspecting everything and reinstalling to see if you can get it closer. There's nothing special about that attachment from what I can remember though.