Hm, does obex really have to be stopped? What happens if it's left alone and rfcomm set to watch a different channel?
I believe obexsrv is a program for sharing files over bluetooth, but I never do that anyway. The problem is that obexsrv insists on listening on channel 1, and my E51 insists on connecting to channel 1 to obtain GPS data. There seems to be no way to configure either of them to use a different channel.