You referred to bundles/bdwebsite/css/*
in your stylesheets
tag.
This way assetic looks for all css files in web/bundles/bdwebsite/css
(a folder that currently does not exist) and not in src/BD/WebsiteBundle/public/css
.
In order to have your files in the right place before executing assetic:dump
...
... use app/console assets:install web
which will copy them to the web folder...
... or my recommendation app/console assets:install web --symlink
for symlinks.