Because vinyl and linoleom flooring is so soft, if someone wears stilettos on it, it can really cause damage to the surface.
There is one thing you can do to try and fix the flooring. You will need a hair dryer and plenty of patience. Wave the hair dryer over the spot and about a foot wide area around it. You want to not just heat the specific dent, but the area around it.
When the flooring is heated, sometimes the floor becomes soft enough that the rings will "release" from the fooring and go back to its original flat shape.
If this does not work - and it won't work on all floors - the floor will need to be replaced. A good scrubbing with bleach may help remove the ringed black marks from the floor, thus making it less noticeable.
In the future, don't let girls in high heels, especially if the heel tap is damaged or worn off, walk on your floor. Good luck!
Gary, February 2010