It is overexposed. Your camera metered the black areas of the scene as medium gray. That cause the shutter speed to be too slow and you also got motion blur. Concert photography is one of the most demanding types on several levels. Getting proper exposure in such an environment is as much an art as a technical skill, and takes a lot of practice to find the best way you can get it.

[Here's one way I prefer to do it.][1] 


  [1]: http://photo.stackexchange.com/a/40762/15871