Problem
Error 65: "Window element does not exist or already exists" for "SO404_InvoiceDetail_bus.pvc"
Solution
If your Shipping Data Entry screen is customized, you may receive this error if it is corrupted by a Sage process.
To correct this issue: Do a full restore from prior to when these issues occurred and proceed to find the following: a backup copy of the SO /Custom/ ###-###/so_shipping.m4l file.
Rename the backup file into the live system and you should be set!