I've installed redmine 0.8.7 on a ubuntu 10.04 LTS without any errors. I can add issues to it but, when it comes to update or even create a quote i get this error from the server on the browser:
Internal error
An error occurred on the page you were trying to access. If you continue to experience problems please contact your redMine administrator for assistance.
and this on the log file:
Rendering /opt/redmine-0.8.7/public/500.html (500 Internal Server Error