If the problem is a bad alarm message at the front of the queue, you should be able to get past it by popping just 1 message from the queue. I think DrNimBUS will do that, but otherwise there is some old standalone utility that Nimsoft had produced years ago that can probably still do it. (The name escapes me, and I am not sure if they would still provide it.)
If you had to flush the entire queue to get things working again, that sounds much more severe.