Loops #VBA Vlookup循环中遇到不适用

我试图在循环中运行一个Vlookup函数。前两个数据（i=3）恢复得很好，但在循环过程中（我确信源文件中存在条件），其他数据（i=10…=>（#N/A））出现错误，因为上下文丢失。你看到我的逻辑有错误吗？ 提前感谢您的回答， 阿尔芒

Sub RAP()

Dim directory As String, fileName As String, sheet As Worksheet, i As Integer, j As Integer
Application.ScreenUpdating = False

'Initialisation of file
directory = "C:\Test"

'Building source filename
Date_fich = Format(Cells(2, 3), "yyyymmdd")

'defining the name of source file
Rac_fich = "MOP-sourcefile"
'Name
fileName = directory & Rac_fich & Date_fich & ".xlsx"
Cells(1, 10) = Date_fich
Cells(1, 11) = fileName

'Files
Dim mat         As Workbook
Dim mat_w       As Worksheet
Dim mat_source  As Worksheet

'Source
Dim mhga        As Workbook
Dim mhga_w      As Worksheet


'searching zone
Dim plage_rech As Range

'variables
Set mat = ActiveWorkbook
ThisWorkbook.Activate

Set mat_w = mat.Worksheets("Test")

'last line
Dim der_ligne As Long
der_ligne = mat_w.Range("A" & Rows.Count).End(xlUp).Row


'Opening mhga (source)
Set mhga = Application.Workbooks.Open(fileName)
Set mhga_w = mhga.Worksheets("Source")


'copy of the source
mhga_w.Copy after:=mat_w
Set mat_source = mat.Worksheets("Source")
Set plage_rech = mat_source.Range("B1:J184")

For i = 3 To der_ligne Step 7
    mat_w.Range("C" & i).Value = Application.VLookup(mat_w.Range("A" & i)
    .Value, plage_rech, 9)
    mat_w.Range("C" & i + 1).Value = Application.VLookup(mat_w.Range("A" & 
    i).Value, plage_rech, 8)
Next


'Closing the source file
mhga.Close (False)



Application.ScreenUpdating = True