moving books from 1.7 to 2.73 problem

I am moving my saved Calibre library (ver 1.7...) into my new library (ver 2.73) and calibre has created the relevant columns from the old metadata. In the bookmark column when I move a book it comes up with: (0)titlepage.xhtml. what does this mean?
When I open my old library it is there also.
Thanks!