ssrs expression invalid swtich case

I am unable to execute the below expression.. 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"
)

ShanmugaRaj