By Default Blueprint uses LPR (Port 515) to deliver a print job to a device. This can be changed to RAW (Port 9100) by changing the configuration for the "Model" that is assigned to the "Device" using the Blueprint Administrator. The error message indicates that a connection to the physical device on port 515 failed for some reason.
The actively refused part of the error suggests that the device is not listening on that port, I would verify that the device is configured to receive print jobs via the LPR protocol. You can use the LPQ command in Windows to verify that the LPD on the device will respond as expected. The below link has information on using the Windows LPQ command line tool.
Answer Link: All Products: Testing a Device's Support of the LPD Protocol
Let us know if this helps.