After cleaning up the code a bit...
waitWindow1.Message = String.Format("Please stand by while the calculations and the data are generated{2}for the date range {0:d} through {1:d}.{2}{2}This may take several minutes depending on the date range entered.",
deBegDate.DateTime,
deEndDate.DateTime,
Environment.NewLine);
(thanks, Greg)
I am still getting the same behavior. I am on a W7/64 workstation.