Never gone out that far but have you tried pushing in at same time as turning clockwise see if you have come off the thread. Might pick up thread again.?
I'm with Dusty on that screw has come right out of the thread, if it will not screw back in with a bit of pressure it could be that what-ever it screws into has dropped away from its location and can no longer be reached.
you already know the man to ask so no point in saying it again.
Good luck and I hope you manage to get it sorted, it's a right downer when something like that happens just at the final stages.