Crystal Reports Date Range

Message


     I have a parameter Date field that I want to show exists within another range of dates
 

{?As of Date} in {Employee_job_History_SCD.DateEffective} to {Employee_job_History_SCD.DateExpires}
 
THE PARAMETER As f Dat is a Date parameter
the  Employee_job_History_SCD.DateEffective is (date, not null)
the Employee_job_History_SCD.DateExpires is (date, null)
 
I keep getting error  on {Employee_job_History_SCD.DateEffective} to {Employee_job_History_SCD.DateExpires} in the following formula
 
{?As of Date} in {Employee_job_History_SCD.DateEffective} to {Employee_job_History_SCD.DateExpires}
 
Error "A date range is required here"
 
Would appreciate any help
 
Thanks