I was having trouble with a Google example for Eclipse/Android. I was getting a duplicate of my main.xml file (the layout file for the project) named main.out.xml. This caused my project to abort with errors. I jumped through a lot of hoops to fix that, including deleting the entire project. Messy. I believe that I finally deleted main.out.xml and I did Project > Clean.
You can stop this trouble from happening. Before you build your project, close all your XML files that are open in the editor. Do NOT leave main.xml open when you build, or you might be very sorry.