$stderr and $stdout are send as part of http response

I am stuck with this issue for some time and I need your help/thoughts.

I am using Ruby 1.8.3 and Rails 0.14.2, running on Linux (Fedora) and
lighttpd.

When ever there is an exception while parsing RSS feeds or Webservice
call,error messages and logs are shown on the browser. This happens only
when there is an exception thrown and on Linux.

lighttpd has write access to the log files. Am I missing any
configurations or settings?

Thanks in advance.

nandhu