點解我用ASP改吾到server上的檔案名稱

我想upload個file上網,然後改名, 但是發生錯誤,如下:
Microsoft VBScript 執行階段錯誤- Error '800a0046' 沒有使用權限 /upload.asp, line 55


Why? 我check過user有執行權, File upload左上去,但是改吾到名....

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strTargetPath = server.mappath("/img") ' 伺服器的目的資料夾
strFile = request.querystring("id")set fs=server.createobject("Scripting.FileSystemObject")
If Request.ServerVariables("REQUEST_METHOD") = "POST" Then ' 建立物件
Set objUpload = GetUpload()
strMessage =""
If Err = 0 Then



For Each objField In objUpload.Items
strFileName = ""
If objField.FileName <> "" Then
strFileName = objField.FileName
' 儲存檔案的內容
objField.Value.SaveAs strTargetPath & "/" & strFileName

source = server.mappath("/img/"& strFilename)
target = server.mappath("/img/"& strFile)

fs.moveFile source, target



End If

Next

response.redirect "member_index.asp"
strFile = ""

else

strMessage = strMessage &"<br>發生錯誤:"& Err.Description

End if