A DOCVARIABLE field is not a MERGEFIELD. That said, to see how to do this and just about everything else you might want to do with dates in Word without VBA, check out my
Microsoft Word Date Calculation Tutorial, at:
http://windowssecrets.com/forums/sho...ation-Tutorial
or:
http://www.gmayor.com/downloads.htm#Third_party
In particular, look at the item titled
Calculate a day, date, month and year, using n days delay. Do read the document's introductory material.
Do note that a VBA solution (if that's what you really want) wouldn't be able to output the results in the same space as the DOCVARIABLE field - it could read the DOCVARIABLE's value directly (without the need for the field), but would need, say, a bookmark as the output destination.