Runtime error 6 "overflow" when doing a inventory switchout on contract.
This can be caused by the inventory line items not having a rate entered for them.
The only way this condition can exist is if the the contract is first loaded under Print / Preload contracts and the individual rates are left blank and the subtotal is filled in instead. The subtotal was designed to be used only when no inventory was selected at the time of printing the contract.
To correct the problem pull up the contract under Point of Sale > Switch Out/Maintenance Hit F11 tab to payment rate, push any key, then enter the individual rates, or at least the total rate under 1 item.
After versionn 3.2.10 the system will be fixed to not allow this to happen.