[libGdx] trouble to getting started with Box2D

hello everyone,
i wanted to use Box2D a long time ago with flash, but i never have the opportunity to do it, so now and since am learning libGdx, am seeing a lot of members here using Box2D in their codes, it appears that using it will make things a lot easier and prettier too, i looked into some examples but still can’t find a clear and well explained one specially for libGdx just to get started, and i always get this error when i try to run a program that use box2D

[quote] java.lang.UnsatisfiedLinkError: com.badlogic.gdx.physics.box2d.World.newWorld(FFZ)
[/quote]
i have no idea how to fix it, anyone can help please ?
PS :
am still looking to find a good place to learn the basics of libGdx (not a special tutorial for Android only )so if any of you lead me into a good link i will be very very grateful

thanx a lot