Solved: Error creating a new Test Case in VS 2010
You receive the error message:
Work item type is not valid. You must specify a valid work item type.
Solution:
You need to import work item categories using witadmin like this:
importcategories /collection:http://server:8080/tfs/collection /p:Project /f:categories.xml
MSDN docs: http://msdn.microsoft.com/en-us/library/dd273721.aspx
You can extract the categories.xml from the Process Template definition.
(Thanks to Ruiz Yi from MSDN Subscriber Support for his post with the solution)