I'm afraid there's no solution to that problem yet, my friend. I've been getting those for quite a while now and have been nowhere near a resolution. I noticed that this problem occurs more frequently with fuller maps, though it is not restricted to those. Another thing I managed to observe is, you can teleport as much as you like within the same map/server, you will not get disconnected, it happens only after switching maps/servers.
If i'm not mistaken, ArenaNet even recognized the issue on a forum post, but they are still working on it, I guess. This is said topic (created May 3rd).
Nevertheless, if you can find any sort of solution, PLEASE, let me know. Best of luck to us.