TFS Web Access is broken

All my charts on web acess are broken and if I click on them they give the following error:

Method 'GetVariableValue' in type 'Microsoft.TeamFoundation.WorkItemTracking.Server.ServerWiqlAdapterHelper' from assembly 'Microsoft.TeamFoundation.WorkItemTracking.Server, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' does not have an implementation.

When I click on my link for product backlog I get this error:

Error(s):

• Unable to get property 'setMessage' of undefined or null reference

  TypeError: Unable to get property 'setMessage' of undefined or null reference
     at Anonymous function (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/Agile/Scripts/TFS.Agile.ProductBacklog.js:4:25855)
     at B (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/corejs?v=HEJc3m-TUp5gkngY8ia8ydgk0vb9xsyzR-zxRx_Wx7k1:435:3197)
     at Anonymous function (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/corejs?v=HEJc3m-TUp5gkngY8ia8ydgk0vb9xsyzR-zxRx_Wx7k1:1291:2665)
     at v (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/corejs?v=HEJc3m-TUp5gkngY8ia8ydgk0vb9xsyzR-zxRx_Wx7k1:1291:1858)
     at Anonymous function (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/corejs?v=HEJc3m-TUp5gkngY8ia8ydgk0vb9xsyzR-zxRx_Wx7k1:1291:2251)
     at l (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/basejs?v=jBIa7AsvDbakV71E4P6aT_e1JcqaY3YeThNH8DW3RHg1:24:20628)
     at c.fireWith (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/basejs?v=jBIa7AsvDbakV71E4P6aT_e1JcqaY3YeThNH8DW3RHg1:24:21547)
     at T (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/basejs?v=jBIa7AsvDbakV71E4P6aT_e1JcqaY3YeThNH8DW3RHg1:24:97243)
     at r (http://anpac-tfs1:8080/tfs/_static/tfs/12/_scripts/TFS/min/basejs?v=jBIa7AsvDbakV71E4P6aT_e1JcqaY3YeThNH8DW3RHg1:24:103858)

Any ideas?