microsoft-test-manager

Microsoft Test Manager 2010 Error: The required category 'Microsoft.TestCaseCategory' does not exist in team project

When I'm attempting to open any of our projects in TFS 2010 with Microsoft Test Manager 2010, I get the error: The required category 'Microsoft.TestCaseCategory' does not exist for project XXXXXXX. What is the reason for this error, and what steps can I take to resolve it? Also, is stackoverflow the right forum for this question? I fee...