Jim,
Look in VFP Tools|Options|Controls, ActiveX controls. Check to see which Calendar control is checked. If it is "Calendar 8.0", look for MSCAL.OCX in your Windows system32 folder. If it is "Calendar", look for MSACAL70.OCX OR MSCAL70.OCX. These are calendar activeX controls.
These need to be installed on your client systems for the calendar to work.

Hopr this helps,

Kim Haggart
Strategic Information Systems
San Bernardino, CA