I'm experiencing some oddity in establishing data call. In my E90 (3rd FP1) the data call established normaly. But in my E61 (3rd) when the data call answered, several seconds later it get disconnected. On the screen (E61) the phone says "Network Busy"

I tried exchange the SIM Card between the two phone. The result is still the same. My E61 never able to establish data call.

Does this have anything to do with the my code? Or the phone's implementation of data call? Or the firmware? Or what?