Box2D Forums

I am currently working on a Dirt Bike Game. But have been facing this random problem where my Bike gets stuck in mid air or starts acting weirdly. After turning on the DebugDraw, i noticed that this was happening due to some Black Line holding my Bike as seen in the image shown below. Sometimes, it goes when i recompile it. But then, it occurs in some other level.So, can someone please tell me what that black line is and how to solve this Problem. Thanks.

http://imageshack.us/photo/my-images/209/bugoda.png