hrm.. now tat u say it and i tested mine, i think mine has too. maybe the gyro?

i never had this problem when i was using my iphone 2g for past 2 and half years with digi. there shouldn't be a need to do any digi network setting for it to work. just put sim card and use it, that's it.

not sure if this helps, but why dont take out your sim card and clean the chip area to try?
try out with another digi sim card that you can find and see if the behaviour is still the same or not.