Hi Brian,

 > 09:20:42.611 gprs.c:863                  pri_activate_callback
> Activating context failed with error: Unknown error type
>

Looking at that line, we are sending a reply right after printing the 
message.  In case the message is NULL, you'd most likely crash inside 
D-Bus or get an assertion of some kind.

The pending variable is also not messed with anywhere else, so you 
should be getting a reply.

The only thing I can suggest is to try and simulate this behavior with 
phonesim and see if you can duplicate / debug it.

Regards,
-Denis