Array loop producing error "Run time error '1004'"

Hi

I have created the array loop below, which should go through the array and put each letter within in the place of the column letter within the lines of code.

 For Each sht2 In Array("F") 'Loop through the vlookup cells and autofill the rest of the columns
       PPNew.Sheets("InputRefapd").Select: Range(sht3 & "1").Select
        Selection.AutoFill Destination:=Range(sht3 & "1:" & sht3 & "30"), Type:=xlFillDefault
Next

However when i run it i get an error of "Method 'range' of 'object' '_global' failed"

Does anyone know why i get this error?

Thanks

Jeskit