Sorry, here's the basic calculation I am using (I need to tell how many pages exist from a certain point to the end of the document):

{= {NUMPAGES} - {PAGEREF FirstSectionBreak }}

If the bookmark 'FirstSectionBreak ' is renamed, or missing, I have seen either a syntax error, or some other error. I'd like to do something like this (pseudocode):

{= {NUMPAGES} - (IF bookmarkExists{FirstSectionBreak }, {PAGEREF FirstSectionBreak }, 0 ) }