To build documentation make sure that the following packages are installed

texlive-science 
texlive-latex-extra
python-pygments
latex-xcolor

Usually the following will install these :

sudo apt-get install texlive-science texlive-latex-extra latex-xcolor 
sudo apt-get install python-pygments (or alternatively run: sudo easy_install Pygments)

Then run the shell script build.sh

./script build.sh

This will build the C/C++ user documentation, OP2 developer documentation, 
OP2 MPI (distributed memory) developer documentation and airfoil 
application developer guide.