You know a fishtail gown is never a good idea when you are dancing, it is a lovely dress, nevertheless.
I have to say that I have never fallen while I was dancing but sometimes you can be surprised when your clothes do something unexpected.
JJ is making a good point. As a woman who is dancing you just have to pay 10x more attention to your clothes than in any other circumstance. You will be spinning, turning and moving at times faster then an aerobics class and expected to look well attired as you do. Wear a slip or else put on something pretty that still covers all your 'stuff' because at some point it is going to be showing, even if you don't realize that it is. I'm telling you I've seen some panties that shouldn't have seen the light of day as they snuck out from under some surprisingly long skirts. Also...please don't do control top panty hose. I am alays horrified when your skits flare up and I see that, maybe some pretty stockings or at least sheer to the waist.
Most of all, please if all else fails do WEAR underwear, I've seen the lack of that on the floor and it isn't a happy thing for anyone, no matter how hot you think you look!!