Males attack females prior to settling down to spawn. If she is not ready, he can kill her so make sure she is plump and showing that first egg.
Another problem can be the temp. Males make nests at a variety of temps but the females sometimes only spawn at certain temps. I find 80-82 degrees best for breeding.
As for the dance, what you are seeing between the 2 males is aggression not breeding dance. You DON'T want to see that in breeding fish. You want to see them embracing not fighting. When I breed, I put the female in a clear jar inside the tank. The male will come over and flair out his gills. If the female is ready, she will get vertical spawning stripes and flair back to the male. It is only after I see this that I release my females. ( You can see a pic of these stripes in my albums in my profile.)
Hope this helps.