I'm pretty sure that this character has been under arrest for a year or so but when I try to drop him, it won't let me. Normally, I wouldn't have cared and just found someone on IRC to give me a hand but I can't access IRC at this time, so, posting here.
It shouldn't "have dropped", it simply should give him the option. And isn't it 3 weeks?
Regardless, it sounds like a bug, so if it gives an error message, post a bug report. If it doesn't give an error, the best course of action is likely to first Contact Support so they can verify your issue.
are you arrested (as in do you see those bars across yer portrait) or are you left locked up in a room?
I would assume the system doesnt count a character without stuncuffs but merely locked up behind a door as arrested.