Forum Post: Crystal Reports XI - optional parameters

I'm trying to create a crystal report with multiple optional parameters.  I've tried the 'not hasvalue' option, but it tells me that "a number, currency amount, boolean, date, time, date-time, or string is expected here" and highlights the HasValue field. I know this will work with the optional value = true in parameter setup in version 2011, but client is still on version 4.5, and therefore Crystal XI. Any help is appreciated! Maureen