That "Command Failed" message you are getting is because TSU cannot communicate with RFX. Could be due to TCP not ready or due to the fact that you have dropped packets in Airport.

If the unit is left on a table, screen goes dark and it goes to sleep. About every 55 seconds, it wakes up to keep the wifi connection alive. I can attest to this for WEP however, I cannot answer for WPA. I suspect that the WPA negotiation sequence is a bit longer.

One solution you have is to return the unit to the dock (or buy an extra dock and power supply from www.servicewidetech.com) such that the screen will go dark but wifi will stay connected.