question

@Vineeth N Please look at the error. It gives you all the information you need:

Flexscript Error MODEL:/Tools/ProcessFlow/ProcessFlow/Assign Labels>labels/1/2 Line 7 Undefined variable shape1 being used.

So this points to the ProcessFlow called ProcessFlow and then to the Assign Labels activity and in there on label 1 it says Undefined variable shape1 being used. So change the text "shape1" to an actual object for instance by using the sampler.