Selenium problem with Watir and Opera in RubyMine

Im trying to create an instance of Opera using Watir in Rubymine using these lines:
require "rubygems"
require "watir-webdriver"
browser = Watir::Browser.new :opera
but that returns an error of
/Library/Ruby/Gems/1.8/gems/selenium-webdriver-2.21.2/lib/selenium/webdriver/opera/service.rb:14:in `selenium_server_jar': Unable to find the Selenium server jar.  Please download the standalone server from http://code.google.com/p/selenium/downloads/list and set the SELENIUM_SERVER_JAR environmental variable to its location.  More info at http://code.google.com/p/selenium/wiki/OperaDriver. (Selenium::WebDriver::Error::WebDriverError)
However if i run these commands in irb i dont get this problem.
I think it has something to do with the fact that ive set up the export SELENIUM_SERVER_JAR=/usr/bin/selenium-server-standalone-2.10.0.jar variable in my .bash.profile in my users/tom/ folder.
I assume that RubyMine must be looking in a difference place than this to get the variable but im not sure where its looking. If someone could point me in the right direction that would be great