I have a similar problem here. It seems to that the bluetooth-stack and/or the bluetooth-integration in kde is broken. I have no idea how to track this down.
I tested with my desktop (latest siduction), my notebook (lenny) and my smartphone (nexus one, android 2.3.6)
Sending files from the notebook to the smartphone works (and vice versa). Sending from the smartphone/notebook to the desktop works, too. In the other direction it doesn't work. Maybe I find a fragment of 16kB. Most of the time nothing. Strange...