It has been awhile since I did this and I forgot to mention the following:
After doing the above, go to the 'Rule Form' tab.
It should display something like:
FIND DateSearches WHERE DateSearches.EndDate<=?'End Date' AND DateSearches.EndDate>=?'End Date'
Change it to something like (change in bold):
FIND DateSearches WHERE DateSearches.EndDate<=?'Start Date' AND DateSearches.EndDate>=?'End Date'
I just guessing, but I think you need two different values for the labels.