I have tried the following combinations for Date1 & Date2:
Both as fill-in formfield bookmarks (as standard text type and also as fixed dd/MM/yyyy Date types).
Date1 as formfield bookmark and Date2 as a { SET Date2 ... } parameter type.
All give the same results.

Regional settings should be either English/Uk or English/Ireland, but the workstation is locked down so I can't confirm that. All dates in the system, windows, and Word/Excel etc default to dd/MM/yyyy which would support the assumption, however.

There are 3 other calculations in the same document which re-use the "+n days" calculation, so they repeat the same bookmarks. These all work correctly, and reference the same Date1 Date2 bookmark information. I have copied the code above to a new blank document and recreated the fields, but the results are still the same.

If I quote out the result bookmarks, I get:
dd = "6"
mm = "-22"
yy = "2014"
so it does not look like the error is part of the formatting switch.


I tried retyping the code more than once, and tried copying the field codes directly from the Date Calculation doc to eliminate the possibility that I typed it incorrectly, but still got the same error. Having said that, I've just tried doing it in the blank document and I am getting the correct result!

Headwrecker!