When I export to my mobile hard dish it showed 1 of the files could not be move to trash.
You seem to be talking about two different problems. Let's take them one at a time.
To export to your mobile drive, let's call it drive M:, you navigate to the M: drive and to some directory in the Export Dialog.
Does the error happen here, or when you press the "export" button?
What is the exact error message?