This error message occurs when a serial number is entered into SpeedShare Server which is not valid for the server. It's probably for a different Qdea product, such as Synchronize! Pro or SpeedShare Pro Server. Remember that a serial number for SpeedShare Pro Server won't work for a SpeedShare Server, and vice versa. Serial numbers which end in -SS5, or -SSU are valid for SpeedShare Server. Serial numbers which end in -SSP1, -SSP5, or -SSPU are valid only for SpeedShare Pro Server. If you have the wrong software (SpeedShare Pro Server instead of SpeedShare Server, for example), you'll need to download the correct software. It's available from the Qdea Web site at http://www.Qdea.com.