I am not sure if it is me - however when I tried to use this tool specifically to find a cache hidden in the month of November 2004 - in the UK (dates between 2004-11-01 and 2004-11-30)
it came up with no caches within this criteria - odd! there must be ?
I expanded it so no country was selected - still no caches
I then selected 2004-11-01 and 2010-11-30 (yes a very large selection - but proved my concern that there may be a bug as still - no caches !!