You're putting in the right link as it went to the right thread name (I'm presuming) but you might want to check to see if you've got the right target forum.
Example of a vBulletin screen for merging threads on another forum I moderate - it's likely that the problem is that you're forgetting to check that the Destination forum is right
On the subject of period sex, I don't really see any problems with it myself. It's not as fun as the blood tends to deaden the sensation, but so long as you put down a towel before there're no mess problems, and the blood washes out pretty easily...