还保护小木屋游戏:菜鸟求教：有关aspupload的的一段代码

在网上看到的：

On Error Resume Next
Server.ScriptTimeOut=999999
if request("act")="upload" then
dim folder,savepath
savepath=Server.MapPath(UploadFilePath)
CreateFolder(savepath)
Set Upload=Server.CreateObject("Persits.Upload")
Upload.SetMaxSize UploadLimitSize*1024, True
Upload.OverwriteFiles = false
if Request.QueryString("PID") = "" then
Upload.ProgressID="010D60EB00C5AA4B"
else
Upload.ProgressID=Request.QueryString("PID")
end if
Count=Upload.Save(savepath)
If Err.Number <> 0 Then
Response.Write "<div style=""color:red;font-size:12px;"">出现错误: " & Err.Number & "、" & Err.Description &"<a href=""javascript:history.go(-1)"">重新上传</a></div>"
End If
If Err.Number = 8 Then
Response.Write "<div style=""color:red;font-size:12px;"">你上传的文件超过限制（"& UploadLimitSize/1024 &"M）<a href=""javascript:history.go(-1)"">重新上传</a></div>"
response.end
end if
dim inputname
dim size,rs_upfile
For Each File in Upload.Files
if not CanUpload(File.ext) then
File.Delete
response.write "<div style=""color:red;font-size:12px;"">"&file.filename &"("& file.size &") 格式不正确！<a href=""javascript:history.go(-1)"">重新上传</a></div>"
else
response.write "<div style=""color:green;font-size:12px;""><!-- "&file.filename &"("& file.size &") --> 上传成功"%><a href="javascript:history.go(-1)">重新上传</a></div><%
end if
next
else

哪为大哥能帮忙说个大概么？那个PID是什么意思呀？？不胜感激！！