While the Powerline Energy Management System is monitoring AC voltages and loads, it does use 12VDC as a control power source.
This could be a 12VDC issue or a 110VAC issue. You will need to use a multimeter measure voltages.
Intellitec made several verisons of the EMS. Here is one of the latest:
http://intellitec.com/PDF/5300740.100.pdf. TOC of their manuals is at:
Service Manuals. Mostly you would just use that for reference as to how their device is operated and wired.
Here is the AC wiring diagram for your system:
http://www.winnebagoind.com/diagram/2007/07_g35l_wire_159396.pdf
Here is a physical view of the interior of your distribution panel that contains the EMS board the display communicates with:
http://www.winnebagoind.com/diagram/2007/07_g-ser_wire_157192.pdf
Does this problem exist on both shore power and generator power?
Verify incoming AC voltage is >= 108VAC
Is your converter putting out at least 13.2VDC (What is it actually?) You most likely have a 3 stage converter so voltage could be 13.2, 13.6, or 14.4 (or 14.6). What previous posters were saying is the converter may be not putting out voltage or is going bad and placing AC noise on the 12VDC distribution buss.
Verify 4 pin connector at display and at EMS board is secure and not corroded. May just be a comm problem between display and EMS board. (corrosion, loose connection)
Verify connections:
Power plug - You said 30 amps so make sure your 30 to 50 amp adpator is good (no corrosion and not breaking down; same for service connection).
Disconnect rig from all 120VAC and verify ATS switch and main breaker panel connections are good and tight. Many people find loose nuetral connections so don't forget those. The EMS board monitors the nuetral lead for amperage value (that donut looking thing the nuetral wire goes through on the EMS board on the way to the nuetral bus bar in the AC distribution panel)
Check 12VDC ground leads for corrosion or loosness.
Dave