Redmine

We have an existing web server that we'd like to host Redmine on. We previously had it working on a test server where Redmine was the only application on it. I know that Redmine is running as we have the service installed as per the install instructions and no errors are seen. We are following the HowTo found here: http://www.redmine.org/projects/redmine/wiki/HowTo_Install_Redmine_on_subdirectory_(sub-URI)_on_Apache.

We have a redmine.conf in /etc/httpd/conf.d configured as follows:
<Proxy *>
Order deny,allow
Allow from all
</Proxy>

ProxyRequests Off
ProxyPass /redmine/ http://127.0.0.1:3000/

Port 3000 is opened on the firewall:
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: http ssh https mysql
ports: 3000/tcp
protocols:
masquerade: no
forward-ports:
source-ports:
icmp-blocks:
rich rules:

When we try to go to the server, https://example.com/redmine/, we get the following error:
This site can’t be reached
example.comlogin’s server IP address could not be found.
The URL in the address bar is: https://example.comlogin/?back_url=http%3A%2F%2Fexample.com%2F

So, the question is: how do we make this work? I feel we're really close, but would really like to find out what we're missing.

Thanks,
Harry