The problem has to do with the server limiting the bit depth that gets passed through the connection. Oracle documents the problem and solution on their site:
In a Remote Desktop session, all environment variables, including display variables determining Color Depth, are determined by the RCP-Tcp connection settings. For example, users can reduce the Color Depth when connecting over a slow connection. The different settings are 15 bits, 16 bits, 24 bits, or 32 bits per pixel. To raise the Remote Desktop color depth:
On the Windows server, launch Remote Desktop Session Host Configuration from the Accessories menu. Under Connections, right click on RDP-Tcp and select Properties. On the Client Settings tab either uncheck LimitMaximum Color Depth or set it to 32 bits per pixel.
Upon unchecking the "Limit Maximum Color Depth" check box and reconnecting to the server, the raster map backgrounds now show up as expected. Note that they also provide option 2 which is to output to an alternate device.