We have the same error on both our Team Web Access AND our SharePoint project portals from our TFS2010 server.
Access through Visual Studio appears to be fine.
However, anywhere a list of work items should appear in either web environment we are instead seeing
Method not found: 'Microsoft.TeamFoundation.WorkItemTracking.Client.DataStore.ScopedFieldDefinitionsClass Microsoft.TeamFoundation.WorkItemTracking.Client.DataStore.NodeClass.get_GlobalFieldDefinitions()'.
We are unable to create items in either web portal as well.
We have tried clearing caches on the TFS and clients then restarting TFS to no avail.
Any suggestions greatly appreciated.