Going by the other forum posts, I would presume that a sure-fire fix has not been completed.
But something that sounds like ISP tech support (and I know I've read it on these forums):
Have you played with what drive goes into what USB port? I have two drives on my PogoPlug. If I plug the drive with alarm into the bottom port, it loads first. If I plug the second drive into the bottom port, I get the lovely flashing green light.
It might be a fluke, but it might be worth fiddling with if you can.