Solved -thanks to hint by Paul Rubin If the preamble reads
\usepackage[numbered,dort&compress]{natbib}
\usepackage[options...]{hyperref}
\usepackage[hypernat]
It resolves the conflict between hyprref and natbib with the sort&compress
option and both dvi and pdflatex compile and the pagebackref option of hyperref
also works appropriately
I hope this is of use to someone
Vivek
