Word 2003 with vba/bookmark issue

Hope I can explain this well enough:

(1) We upgraded from Word 2000 to Word 2003
(2) We have a vba application that replaces bookmarked text with fields selected from a series of screens to create documents
(3) These documents are assigned a six digit number
(4) When we take an old 2000 document and copy it into 2003 and replace the document# it looks fine.
(5) But ... after we print the document, the document# becomes a combination of the old doc# and the new doc# ( 12 digits in length ).

Any suggestions?