The user's Windows Region and Language settings have the short date format set to something other than MM/dd/yyyy (or M/d/yyyy).
Set that to MM/dd/yyyy (via Additional Settings, Date tab, if necessary). M/d/yyyy will also work. Note: This setting is per-user; if a different Windows user logs onto the PC, this setting will need to be set for that user before the Get Data step in InventoryControl.
Quit and relaunch InventoryControl for the change to take effect.
This will fix any future data transfers from the mobile device back to the PC, but it does not fix any existing mobile files that were transferred before.
However, you should be able to fix them. On the Step 5 Process Transactions window, go down the list of error lines, edit each transaction, then click OK without making any changes. That should clear the error for that line.
When there are no more error lines, click Finish.