eclipse tells me my project has errors, nothing is red-highlighted

Question

This happened to two programs of mine now and makes absolutely no sense. It usually comes about when I'm adding a resource file (in this case, a menu). In the package explorer: -the project name has a small red x, indicating that there is an error in one of its files -none of the sub-folders or files have an x or show any red highlights

None of my code has errors! Ocasionally, I see this: [2010-09-02 16:09:20 - FallDown] 'default' is not a best match for any device/locale combination. [2010-09-02 16:09:20 - FallDown] Displaying it with 'Normal, Not Long, Landscape, Medium Density, Finger, Soft, Qwerty, Trackball, 480x320'

What is going on?

Answer 1

Window --> Show View --> Problems. This should display a list of the specific problems that Eclipse is 'worried' about.

Answer 2

Usually what I do in this case is to call "Project > Clean" from the menu.