Hi tsindos,
That code comes from my Microsoft Word Date Calculation Tutorial, at:
http://lounge.windowssecrets.com/ind...owtopic=249902
or
http://www.gmayor.com/downloads.htm#Third_party
It would appear that you've tried to combine a field code from the tutorial that used error-checking with the field for adding months to a date, and got some of the syntax wrong - specifically, a '(' before the first 'Delay' reference. If your formfield has data entry validation, you don't need the additional error-checking code, and it can be reduced to:
{
QUOTE
{SET mm{=MOD(ABS({StartDate \@ M}+Delay+11);12)+1}}
{SET yy{=INT({StartDate \@ yyyy}+(Delay+{StartDate \@ M}-1)/12)}}
{SET dd{=IF(({StartDate \@ d}>28)*(mm=2)=1;28+((MOD(yy;4)=0)+(MOD(yy;400)=0)-(MOD(yy;100)=0));IF((mm=4)+(mm=6)+(mm=9)+(mm=11)+( {StartDate \@ d}>30)>1;30;{StartDate \@ d}))}}
"{dd}-{mm}-{yy}" \@ "dddd, d MMMM yyyy" \* Charformat}
Note that I've bolded the 'Q' in 'QUOTE' and added a Charformat switch. That's the correct way to alter the field's formatting - not by trying to apply bold formatting to the lot (which often adds numerous unhelpful Mergeformat switches).
Also, your formfields need the 'calculate on exit' property set, otherwise, the calculation won't occur.