错误91 - 对象变量或未设置块变量

Question

我正在编写excel vba并遇到此问题Error 91 - Object variable or with block variable not set。我似乎无法找到代码问题的位置。这是我的代码：

Private Sub cmdUpdate_Click()
    Dim findValue As Range
    Dim cNum As Integer
    Dim DataSH As Worksheet

    On Error GoTo errHandler:

    Application.ScreenUpdating = False

    Set DataSH = Sheet1

    lstStudents.RowSource = ""

    Set findValue = DataSH.Range("A:A"). _
    Find(What:=Me.txtStudNo2.Value, LookIn:=xlValues, LookAt:=xlWhole)

    findValue = txtStudNo2.Value
    findValue.Offset(0, 1) = txtStudNo2.Value
    findValue.Offset(0, 2) = txtName.Value
    findValue.Offset(0, 3) = cboCollege2.Value
    findValue.Offset(0, 4) = cboCourse2.Value
    findValue.Offset(0, 5) = txtMobNo2.Value

    Unprotect_All

    DataSH.Range("A1").CurrentRegion.AdvancedFilter Action:=xlFilterCopy, _
    CriteriaRange:=Range("Data!$L$1:$L$2"), CopyToRange:=Range("Data!$M$1:$Q$1"), _
    Unique:=False

    If DataSH.Range("M2").Value = "" Then
        lstStudents.RowSource = ""
    Else
        lstStudents.RowSource = DataSH.Range("outdata").Address(external:=True)
    End If

    Sheet2.Select

    Protect_All

    On Error GoTo 0
    Exit Sub
errHandler:

    Protect_All

    MsgBox "An Error occured " & vbCrLf & _
            "The error number is: " & Err.Number & vbCrLf & _
            Err.Description & vbCrLf & "Please notify the administrator"
End Sub