What version are you running? RBTools-0.3.3 What's the URL of the page containing the problem? local What steps will reproduce the problem? 0. Do not install GNU diff (on a Windows box) 1. Use post-review in a Perforce workspace 2. It gives an uncaught exception and a call stack 3. What is the expected output? What do you see instead? It would be good if post-review giving some informative error on not being able to locate GNU diff. What operating system are you using? What browser? Windows XP Please provide any additional information below. I found that a similar check and informative error message already installed on Svn and ClearCase: check_gnu_diff(). I suggest call this check for Perforce too.