no resource found that matches the given name

Did you check to ensure that you have the string resource defined in res/values/strings.xml?

<string name="app_name">"My App"</string>

Sometimes, I've noticed eclipse will also throw errors that are hard to track if you have any .xml files with errors. I don't think the parser recovers well and sometimes the errors you get can be misleading.

I also had the same error with my images .. Just rename the extension from ".png" or whatever you have to ".jpg" then they work fine after cleaning the project and re compiling it.

One Reason Can Be as in my case a bug in the string GUI when you add and delete items in some sequence

solution: simply open the strings.xml in the XML mode not GUI you will find it different and has obvious not valid extra texts pasted around or at the beginning ; although it does not give an error on the file strings.xml fix them and then clean and run