"The item does not exist at the specified version"
If you ever get this error from TFS, then double-check that the item you’re requesting does actually exist in the repository. I was having this problem with one of our projects, where I was asking TFS for the latest version of this item:
$/Online Services Solution Template/Main/Source
But after much investigation (including querying the TFS SQL database directly) I discovered that the correct item name was in fact:
$/Online Services Solution Templates/Main/Source
So another way to read that error message would be as “I can’t find an item with that name, are you sure you typed it correctly?”