Webdriver Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms
Don't know if you resolved this problem, but I have just resolved the same issue from the other side.
It appears Selenium and Firefox have difficulty talking to each other - I suspect Firefox 'evolve' changes over a number of releases, so backward and forward compatibility are not always guaranteed, and incompatibility always seems to generate the same error.
My problem started when I moved from FF 15 to FF 16. Running on Ubuntu, this happens auto magically along with other upgrades but I believe this was the critical change.
The problem was resolved by moving from Selenium 2.24.1 to Selenium 2.25.0
As the selenium change is just download the jar file and run it instead of the old one,it's worth trying this as a quick and easy troubleshooter - if it doesn't help, just switch back. In your case, I'm not sure which version of Selenium to try, but I think 2.24 should work with FF 10.
Another issue I have found in the past is that Firefox would not run as root on Ubuntu. This happens if Selenium is running as a service, or possibly if it is fired up from a bash script or cron job. This may explain why it runs for you but not for Jenkins.
I had a similar issue. Maybe this answer will help you as well.
It looks like you have two different errors going on:
Unable to connect to host 127.0.0.1 on port 7055Error: no display specified
The reason for the Unable to connect error is that the version of Selenium Server does not know how to work with the newer version of Firefox. You need to download a newer version of the Selenium Server that supports the newer version of Firefox.
The reason for the Error: no display specified error is that Firefox is being launched, but there is no X server (GUI) running on the remote host. You can use X11 forwarding to run Firefox on the remote host, but display it on your local host. On Mac OS X, you will need to download XQuartz in order to use X11 forwarding.
You need to check the browser compatibility before opting to test with Selenium:
https://github.com/SeleniumHQ/selenium/blob/master/java/CHANGELOG
This might help to answer the above question.