xrdp does not work correctly

There are NC600 terminals that work with RDP protocolto connect with a GNU server. We can have Trisquel with a VNC server and xRDP to login to the terminal as a Trisquel user. On version 5.0 we had no problem. On version 5.5 we have a white screen with nothing but the pointer. On Ubuntu 11.10 and 12.04 it works flawlessly. The problem is on any server hardware.

To reproduce:
- install xrdp and tightvncserver
- boot NC600 terminal
- connect to server IP address.

Side note:
We are trying to install a free version of GNU into the terminals and are willing to pay someone to do it. The processor is an ARM9.