Options Indexes FollowSymLinks
ErrorDocument 404 /error404.html

RewriteEngine On

# rewrite any request to a unknown file to pmd-5.0.0
# (or whatever subfolder the first rule will set to the environment variable PMD)
# but redirect only if the file exists there
RewriteRule .* - [E=PMD:pmd-5.0.0]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond /home/project-web/pmd/htdocs/%{ENV:PMD}%{REQUEST_URI} -f
RewriteRule .* /%{ENV:PMD}%{REQUEST_URI} [L,R]