类型不匹配错误和对象定义错误？

Question

此类型的错误仅在“ aStr”处出现。但是“ bStr”采用字符串值。同样在if语句的情况下，我得到对象定义的错误。

Dim i, a, b, rowInt As Integer
Dim colC, colE, colA, colG, aStr, bStr As String
Dim cellRef1, cellRef2, cellRef3 As String
Dim delRef1, delRef2 As String

rowInt = Evaluate("LOOKUP(2,1/(A:A<>""""),ROW(A:A))") - 11

Sheets("Orders").Select

colA = "A"
colC = "C"
colE = "E"
colG = "G"

i = 1
     Do
          Sheets("Orders").Select
          a = i + 10
          b = i + 11
          aStr = a
          bStr = b
          cellRef1 = colC + aStr
          cellRef2 = colC + bStr
          cellRef3 = colE + aStr
          cellRef4 = colE + bStr
          delRef1 = colA + bStr
          delRef2 = colG + bStr
          Range("D1").Value = i
          If Sheets("Orders").Range(cellRef1).Text = Sheets("Orders").Range(cellRef2).Text Then
               Range(cellRef3).Value = Range(cellRef3).Value + Range(cellRef4).Value
               Range("" & delRef1 & ":" & delRef2 & "").Delete Shift:=xlUp
               rowInt = rowInt - 1
               i = i + 1
          Else
               i = i + 1
          End If
     Loop While i = rowInt

End Sub