expression invalid swtich case

I am getting error when i see the report preview as The defenition of the report is invalid The value expression for the text box'Text Box1' has a nested aggregate that specifies a dataset scope.Inner aggregates cannot specify a dataset scope. My Expression is= "Record contains " + Switch( Sum(Fields!FQ.Value, "ds") <> 0 and Sum(Sum(Fields!QC.Value, "ds") + Sum(Fields!QA.Value, "ds") )<> 0 , "Fit and Auto", Sum(Fields!FQ.Value, "ds") <> 0 and Sum(Sum(Fields!QC.Value, "ds") + Sum(Fields!QA.Value, "ds") )= 0 , "Fit", Sum(Fields!FQ.Value, "ds") = 0 and Sum(Sum(Fields!QC.Value, "ds") + Sum(Fields!QA.Value, "ds") ) <> 0 , "Auto")