(See the best response by Kaiochao.)
Problem description:After compiling my game with no errors, and then I run my game. I can make one step then I cant move the icon anymore.

This is pretty open for any possibilities really. Did you overwrite Move? Did you place any dense object? Is the world.maxx and maxy > 2?
How would I overwrite move? And its there isn't a dense object.
Best response
"Overwriting Move" means "Move(" is written in the code somewhere under your player mob or client. This is usually done for tile-based games to implement step delays. It's possible you're trying to temporarily lock movement, but instead you're ending up permanently locking it.