Microsoft VBScript 运行时错误 error '800a0005'

无效的过程调用或参数: 'Mid'

G:\王鹤\齐齐哈尔市摄影家协会\aspWebServer_bkill.com\aspWebServer\www\admin\KS.Template.asp,line 132

  With Response
  InstallDir=KS.Setting(3)
        If CurrPath = "" Then
   ParentPath = ""
   CurrPath= InstallDir & KS.Setting(90)
  Else
  
   ParentPath = Mid(CurrPath, 1, InStrRev(CurrPath, "/") - 1) 此处是132
   
   If ParentPath = "" Then
    ParentPath = Left(InstallDir, Len(InstallDir) - 1)
   End If
  End If
  If Right(CurrPath,1)="/" Then CurrPath=Left(CurrPath,Len(CurrPath)-1)  
  
  

asp版本，发这里干嘛。