After an update of puppet & passenger i got this error:

Warning: Unable to fetch my node definition, but the agent run will continue:
Warning: Error 400 on SERVER: invalid byte sequence in US-ASCII
Info: Retrieving pluginfacts
Info: Retrieving plugin
Info: Loading facts
Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Failed when searching for node xxxx: invalid byte sequence in US-ASCII
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping ru

You can fix it by adding this line on the puppet master and restart passenger (-> restart apache2 or nginx):

echo „Encoding.default_external = Encoding::UTF_8“ >> /usr/share/puppet/rack/puppetmasterd/config.ru
service apache2 restart

After this puppet should run in UTF-8 Mode and the problem should be solved.