Traping Error number 68??

[Nida]

hi
i have a drivelistbox ,dirlistbox and filelistbox
i want to trap error( Device unavailable "68")
i placed the following code

Private Sub Drive1_Change()
  On Error GoTo EH:
EH:
If err.Number = 68 Then
    GoTo DISK
     End If
 DISK:
   MsgBox "Drive A:\ is Not Ready"
    Drive1.Drive = "C:\"
     Exit Sub
 Dir1.Path = Drive1.Drive
   End Sub

when i run the program the error occured on clicking any drive(all drives)
what i have to do?
THANKS