Capybara element not found just on Travis - selenium

Question

I'm trying to put the free software where I'm one of the collaborators to run the acceptance tests on Travis. Everything went very well except for the acceptance tests with selenium.
And this is a difficult issue because the software uses only the gem versions avaiable on Debian 6. So, everything is really outdated.
Being more specific, just the steps where I'm looking for some text on the screen, with the step:
page.should have_content(text)
I've already tried to:
to add some waiting since it could be looking for the element before it was rendered;
update the xpath;
remove the webrat, because I've read that it could be conclicting with capybara;
run the tests locally with xvfb;
create a VM with Ubuntu Server 12.04 32 bits (Travis version), install everything and run the tests on xvfb;
update Capybara from 1.1.1 to 1.1.4.
But the problem persists:
# features/step_definitions/web_steps.rb:107
Unable to find xpath "/html" (Capybara::ElementNotFound)
(eval):2:in `send'
(eval):2:in `text'
./features/step_definitions/web_steps.rb:110
./features/step_definitions/web_steps.rb:14:in `with_scope'
./features/step_definitions/web_steps.rb:108:in `/^(?:|I )should see "([^"]*)"(?: within "([^"]*)")?$/'
plugins/mezuro/features/repository.feature:101:in `And I should see "My Name"'
Here is the link for the build:
https://travis-ci.org/rafamanzo/mezuro-travis/builds/6231714
Anyone have any idea? I'm afraid that it is related with the gem versions and I'll not be able to fix it by any means.
Here are links for what I was able to find about it on Google:
https://groups.google.com/forum/#!msg/ruby-capybara/PDr7sZ124Vw/qLXqHXs0XdMJ
https://github.com/rspec/rspec-rails/issues/406
Thank you very much!