Try to use Remote Desktop Manager 64bit. To do so, launch Remote Desktop Manager64.exe from the installation folder instead of Remote Desktop Manager.exe.
Uncheck Bitmap Caching and Themes under the Experience tab in the properties of the RDP session.
Uncheck Themes And Bitmap Caching
Close Remote Desktop Manager,rename default.rdp file in My Documents to default.old, restart Remote Desktop Manager and try to connect with RDP.
Login in to the target machine,by directly going to the console of that server or by any tool like VNC so that we can get access to that machine.
1.Right Click on the Desktop
2.Select the Properties
3.There DropDown the Themes and select the theme other than the current one.
4.Click on Apply, OK
Now try to connect that machine remotely.