You are attempting to access an undefined variable. For example, if the variable
huh has not been defined, a call to it generates this error:
huh = 55;
This error can appear only when the compiler is running in strict mode.
ActionScript error #1120 means that an object “property” within Flash or Flex is not defined. But this doesn’t really help you fix it. One main reason for this AS3 Error is that you haven’t given the MovieClip or Button an instance name when you placed it on the stage in Flash. Another reason is that the reference is not correct.
Give your instance the proper instance name
Flash properties dialog without an instance name Flash properties dialog without an instance name
Flash Properties Dialog with Instance Name Flash properties dialog with MovieClip instance name
Check that your reference is the proper instance name