The warning:
! pdfTeX warning (ext4): destination with the same identifier
(name{page.1}) has been already used, duplicate ignored
arises because of duplicate page numbers in your document. The
problem is usually soluble: see
PDF page destinations - which
answer also describes the problem in more detail.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=hyperdupdest