> It is supposed to get the system century and then place it
> on the century part of the date.


From the FoxPro 2.6 DOS help:

Use SET CENTURY to specify how date variables and functions are displayed. 

ON
	SET CENTURY ON specifies a four-digit year format that includes 10 characters (including date delimiters).

OFF
	SET CENTURY OFF specifies a two-digit year format that includes eight characters and assumes the twentieth century for date calculations. This is the default setting.

To get rollover functionality in 2.6, I'd suggest checking out Christof's article at http://www.advisor.com/wArticle.nsf/w/FA9803.LANGC01.