What is the exact message you receive when you try and 'transfer'?  Does that same serial number "already" exist in the "to warehouse"?

You are correct, I didn't notice that it was placed in the standard warehouse during physical inventory, even though it should have been placed in the repair warehouse.  Thank you for your help.

You are correct, I didn't notice that it was placed in the standard warehouse during physical inventory, even though it should have been placed in the repair warehouse.  Thank you for your help.