how to fix an error like this

08/08/2009 19:49 Pete1990#1

Ok now and then i see this error and i dont know what to do about it

HTML Code:

System.NullReferenceException: Object reference not set to an instance of an object.

What does it mean how can i fix them?

08/08/2009 21:57 CoAttack#2

you probably went too much on your array i think something about it.

08/08/2009 22:18 samehvan#3

that means u r trying to do an operation on a null variable ,too many cases may coz that so it depends on ur code line