Another thing you should check are the Launch Control Options. Maybe you have "Move Original" enabled there. If so, make sure to update to GarageSale 7.0.8 and check the Launch Control Options the next time you start a listing.
From the release notes:
"The preferences for moving & duplicating items when starting auctions are now saved separately from those used when re-listing (this should prevent users who overlooked their still active 'Move To Trash' setting used when re-listing from getting confused next time their listing 'vanishes' into the Trash after uploading them to eBay"