D/C relogging problems.

Every time I am in a dungeon, and I d/c, I have to wait around 5mins for the "You are still logged in" message to go away, and when it does, I have been booted from the dungeon without fail, probably due to the inactivity thing. I cannot reduce the number of D/Cs as it is due to where I live, and the fact that there is crappy internet here. What can I do about the inability to log back in for 5mins? This didn't used to happen, it's started happening around 3 patches ago.

It's impossible to get any dungeons done when this happens...

However, in PVP if I d/c, I can always rejoin right after I d/c, no error message or anything.
Why are dungeons and pvp different in this way?