Web Inspector on the PlayBook is a 2011 app that may not be compatible with the current applications on todays web servers. It was originally designed for developers to check their application on the tablet. Unless someone knows if the application was ever updated you may not be able to do what your trying to do successfully.
here are a couple of links that may offer some help.
https://developer.blackberry.com/htm...inspector.html
https://developer.blackberry.com/pla...987477_11.html