I use ObjectDock Pluse on both an XP Home 32 bit and Vista Home Premium 64 bit computers. I have the zoomer dock at the bottom of the screen as you do and set to hide in back ground when not in use. I have no problems getting full windows of any app that I use.
Try switching to one of the other options in interaction, make sure it works and then go back to hiding in the background and see what happens.