I second Aslan's comment, take her to a vet, to eliminate possible medical problems.
If she clears the health bill, then it could be behavioural problem, my mom's dog also has a weird phobia of smooth floors, like laminated or tile...and if you put something on the floor, that he hasn't seen before - he freaks. Like a bright bag or something. He is also afraid of chewing gum, he runs away if I am chewing a gum, and only a gum, otherwise he is there begging.
pups!