NullReferenceException to an obvious boolean reference.

Please help me, I cant get this to work and It worked in another project... why is not working here?

Obviously I am retriving a boolean that do exist in a GameObject called: CheckGrounded inside of the component that is called: CheckGrounded, i have tried change names, caps, everything and it dosnt work...

the error "NullReferenceException: Object reference not set to an instance of an object" is obviously wrong...

The code had worked for just 1 time... then hit the play button for a second time and it started acting like this... (Using C#)