If you find this error message on your Android eclipse Console, this is because you have a resource xml file that has a invalid file name, you can only have alphabets a-z (i.e. Lowercase) and numbers 0-9 and dot (.) or underscores (_).
So if you have a xml file with the below file names they are invalid,
1. Button_layout.xml => Cannot have Capital Alphabets
2. login-form.xml => Cannot have - symbol only _ allowed
3. FileName.xml => Cannot have Capital Alphabets