我收到错误消息“对象变量或未设置块变量”

Sub Exercise()              ' ' to read data from file tasks.xls and 
    Dim Arr As Variant, Arr1 As Variant  ' feed the task name for the person
    Dim iRow As Integer                  ' in a month in this file
    Dim iCol As Integer
    Dim i As Integer, x As Integer
    Dim name As String

    'name = Cells(1, 1).Value
    Arr = Workbooks.Open("E:tasks.xlsx").Sheets("Sheet1").Range("B1:E1").Value
    Arr1 = Workbooks.Open("E:tasks.xlsx").Sheets("Sheet1").Range("B2:E2").Value
    Sheets(1).Cells(1, 1).Select                  ' go to beginning cell

     For i = 1 To Arr1(1, 1)
        Cells(6, 4 + i).Value = Arr(1, 1)
        a = i + 4
    Next i


    For i = 1 To Arr1(1, 2)
        Cells(6, a + i).Value = Arr(1, 2)
        b = a + i
    Next i

    For i = 1 To Arr1(1, 3)
        Cells(6, b + i).Value = Arr(1, 3)
        C = b + i
    Next i

    For i = 1 To Arr1(1, 4)
        Cells(6, C + i).Value = Arr(1, 4)
        d = a + i
    Next i                                               

    Do While ActiveCell.Row <> Sheets(1).Range("A" & Rows.Count).End(xlUp).Row
                                                 ' some times i get infinte loop
    ActiveCell.Offset(2, 0).Select              ' span till the last
    name = ActiveCell.Value                      '  non empty  row
    Arr = Sheets(1).Range(ActiveCell.Offset(0, 1), ActiveCell.Offset(0, 5)).Value
    Arr1 = Sheets(1).Range(ActiveCell.Offset(1, 1), ActiveCell.Offset(1, 5)).Value


    With ThisWorkbook.Sheets(3)            'algorithm to search the name                                                                                         '                                               positon in this excel file
    Dim findrow As Range
    Set findrow = .Range("A:A").Find(What:=name, LookIn:=xlValues)
   iRow = findrow.Row                   ' required row where name is found

    For i = 1 To Arr1(1, 1)
        Cells(iRow, 4 + i).Value = Arr(1, 1)
       a = i + 4
    Next i

    For i = 1 To Arr1(1, 2)
        Cells(iRow, a + i).Value = Arr(1, 2)
        b = a + i
    Next i

    For i = 1 To Arr1(1, 3)
        Cells(iRow, b + i).Value = Arr(1, 3)
        C = b + i
    Next i

    For i = 1 To Arr1(1, 4)
        Cells(iRow, C + i).Value = Arr(1, 4)
        d = a + i
    Next i

    Loop

End Sub
Sub Exercise()              ' ' to read data fr