Thank you!!
Whew, I'm pretty new to this crosstab query stuff, but finally figured it out.
For those newbies out there like me, in the parameter dialog box everyone says needs to be filled in also, remove the "Between" and "And" and all the brackets for EACH field. Essentially, you'll have two lines in this box, one for the start date field and one for the end date.
Brackets - no brackets... ahhhh!
Thanks for your help!