This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
This wouldn't have anything to do with "path variables;" it's more a question of how your web app is configured (unless it's the even simpler problem that you don't have a file by a given name.) This isn't really Tomcat-specific; if you tell me a little more about your web app I'll know where to move this topic to so you can get the help you need.