Error in Update work items- Level 3 advanced Assignment 1

Hi All,

I have tried multiple to run the workflow, but everytime I am stuck in Update Work Items file. Error is in attach browser window where we update the work items by adding the comment. Error is also in the Type into activity where we add a comment.

I am selecting proper suggested selector for adding comment and attach browser. I dont know what is going wrong. Please help me resolving this (1.3 MB)