lyx cant find .cls files

[navaja]

i get textclass error when loading an example cv from 
/usr/share/texmf/tex/latex/lyx/examples/cv.lyx the .cls file is in 
/usr/share/texmf/tex/latex/lyx/cv.cls but lyx doesent seem to be able to 
find it. where do i specify this directory as the .cls files directory?