I setup media browser on my windows 7 media center. It would open fine on the media center but it would'nt open from my xbox 360 on my tv.
I discovered the issue is a permissions problem. The media browser does'nt have access to its config files.
To resolve the issue first off you need to reveal hidden files and folders, ctrl+f10, tools, folder options, view and select show hidden files and folders. On the media center go to the users folder, you should see a user called mcx1-yourcomputername. This is the extenders account used by media browser to access your media. Next open the folder C:\ProgramData\ and locate the media browser folder. Right click on it go to properties security, advanced, change permissions, add, advanced, find now and select your mcx1 account then select ok and check off full control. Do the same thing for the folders that store your media, such as movies, pictures and TV etc. You can also add the everyone group but its much more secure to add the mcx1 account.
Other things that can cause the media browser not to respond is if it cannot locate something you have specified in its config. The weather feature appears to have caused lots of problems. If its not configured correctly the browser will not respond. So uncheck the weather from the config tool.