asterisk users - Jan 2004 - strange problem with grandstream software 1.0.4.39

hi all

I have a strange problem that started right after an upgrade from 
1.0.3.81: Every now and then the display flashes 484 when the phone is 
idle, on hook. Early Dial is disabled, and I don't understand anything. 
Everything works fine apart from this annoying flashing...

Anyone that knows what this might be?

regards

roy