I don't know that LOR can handle a USB pixelnet dongle. It does not use E1.31 as there is no Ethernet network involved. For this to work, LOR would need to use the USB interface with 4096 channel support.
Instead, I suggest you use your computer's network interface and the E1.31 capability in LOR to communicate over a network connection to a etherdongle. The etherdongle will generate pixelnet and the rest of your setup will work as it did before.