As you may or may not be aware, this particular machine can be used as either a condenser style dryer or in the more traditional hose draining style manor and as such an outlet pipe is located on the rear (top left corner) so that provision for external draining can be made.
Make sure that this outlet pipe is not leaking when the machine is in use otherwise water will leak from this source instead of being fed to the pull-out style water bottle.
The pipe is closed off with a screw style cap which has a disc & a rubber seal inside of it. this cap is either loosely screwed in place or the rubber seal has perished, and is the most likely cause of your problem leak.
Hope this helps.
Simon
March 2006