This means that you have a typo someplace, it's basically the equivalent of a web 404 error on your code, even if the code may be potentially valid from the scripting environments perspective.
BAD CODE:
object[someproperty];
GOOD CODE
object(someproperty); like in getterFunction(someproperty);
In our case this happened when changing direct access to a associative array into a getter and setter function.
{ 1 comment… read it below or add one }
You also get a ReferenceError if you use getDefinitionByName() or ApplicationDomain.currentDomain.getDefinition(), when the class you trying to access hasn’t been defined in the ApplicationDomain.