Welcome DnA, I have a 12 year old lab who is afraid of our floors. Mostly the bedroom floors. Sometimes she's fine with them, other times she freezes and won't move, just stands and shakes. I also had floor runners all over the bedroom until we changed the floors and that was good, the runners worked of course, the new floor was better, but now she's getting a bit shy of the new floor too.
I think with you pup, and mine, something has scared them into running and then they slip. The next time they remember the slip so they run to get away from it, and yup, just like they though, they slip again. A friend of mine who is a trainer has recommended leashing the dog and walking back and forth, back and forth. Do not give enough leash that the dog can pull away from you. Just make them walk and realize that it's not dangerous. Reward a good walk.
Now ours is having trouble because we have 2 new puppies. When the corner her in the bedroom she tries to run out and slips. She rarely has a problem with the floor if the puppies are not around!
I have also heard lots of good things about the thundershirts. One of my puppies is very nervous of loud noises (like trucks) so we're working on that, but I'm worried about thunder, thankfully we don't get much of it out in the West here.