Thanks, mates, but that's not the problem. You have to fill out all the fields to enable the OK button, but the problem was that I couldn't: clicking on Driver didn't give me the driver selection screen, clicking on Replay didn't give me the replay selection screen, and so on. The only buttons that worked were Description and Cancel.
I also have three pending reports whose oldest is 10 days old, now, BTW. That's why I thought that reporting might be disabled on purpose.