Without any warning, all of the sticky threads in many forums of my web site got down. When I opened the messages, they appear like they are up (i.e. they show the "get down" icon), but if you try to send the threads up again, it doesn't works. No error messages found, but that day the hard disk in my server got out of space. That was fixed, but sticky threads doesn't works yet.
I'm using UBB 5.45c.