I have a problem

I followed the tutorial “How to make a 2D Platformer - PLAYER HEALTH - Unity Tutorial” and he gave me that error:

CameraFallow script: http://pastebin.com/zun4LrMm

Player script:http://pastebin.com/r2GbNywG

GameMaster script: http://pastebin.com/fNjLnbrB

How can fix it?

Most likely you failed to drag a reference into some public inspector variable. Go back and check your work related to the inspector variable that it is referencing on the line number of the error above.

i tried to add this:

if (target == null)
      return;"

but nothing.