When I say forwarding from apache, I think I wasn't being specific enough - I'm just using: RewriteRule ^/jasperserver/(.*)$ http://localhost:8180/jasperserver/$1 [P,L] In other words, tomcat is the one serving the instance on port 8180, and I can connect to this directly and verify the error is here, not in the forwarding to apache. I guess that part of the setup isn't relevant, I was just mentioning it for completeness sake. Thanks for responding in any case, and if you have any ideas about the error message itself, let me know. Cheers, Tom