The latch being open as you found it means it could be busted (it looks a bit messed up). You could try just wedging the ribbon in there without using the latch.. put a small piece of plastic on the non-lead side of the ribbon (e.g. Scotch tape) and shove it in. If too loose add another small sheet of plastic. Repeat until you have a good purely friction fit, not so good that the ribbon is not going all the way in though. There could also be some junk inside the female end, might be worth trying to clean it out.