When you pour your fresh water into the reservoir, you might be letting some of your water escape or drip into the well area where inner tank slips in and rests on top of the warming plate. There is a drain hole next to the warming plate that lets such spills escape through the machine. This may be your leak, since it doesn't appear to be leaking your entire reservoir water as described in your posting.
One suggested remedy is to try using a funnel or measuring cup to carefully fill the reservoir water a few times (no drips outside of that rear right corner fill hole), just to check your accuracy. If it stops the leak, it's a simple fix (just keep using the funnel if you have shaky hands like mine when you fill it each evening:-). If your leak continues to take place, you may have a crack in the water reservoir somewhere.
Rob, January 2007