I've got the same problem in crucible and tower. My ISP (DSL) let me change my DSLAM configuration and with Fastpath configuration I've got this error constantly but with annex M the error seems to have disappeared. It seems a bandwidth problem with my upload speed because two modes don't have any packet loss problem. In Fastpah mode the speed is 10/0.7 Mbps and in Annex M mode is 12/1 Mbps. It's the first time I've got this problem, of course, in other online games (like Battlefield with 64 players) I've been playing for hours without disconnections.
I've never seen the bandwidth requirements of this game but it seems that you need, at least, 1 Mbps of [b]stable[/b] upload speed.