Depending upon where you are in the world, it could have been caused by humidity. A lot of color added to fondant can also make it sticky, if it has not set up for a few hours or overnight.
I prefer to lightly grease my rolling surface with shortening (Crisco, Trex), then wipe off any excess with a paper towel. This works particularly well if you are using a silicon mat which can be picked up to position the fondant on the cake.
Sugar Sugar by SSmiley
