Error when loading application-missing R file and action string

I am complete novice -I want to create a button scrolling activity. Everything is green in the Main Activity and the string XML file. When I try and run I get the following errors.

• the R .java file goes missing. And is not recognised in the activity_main.java. 2.It flags up error in menu_main.xml "@string/action strings".

Error:(4, 60) Grade: Execution failed for task ':app:processDebugResources'.

com.android.ide.common.internal.LoggedErrorException: Failed to run command: C:\Users\Nooles\AppData\Local\Android\sdk\build-tools\21.1.2\aapt.exe package -f --no-crunch -I C:\Users\Nooles\AppData\Local\Android\sdk\platforms\android-21\android.jar -M C:\Users\Nooles\AndroidStudioProjects\maps\app\build\intermediates\manifests\full\debug\AndroidManifest.xml -S C:\Users\Noodles\AndroidStudioProjects\maps\app\build\intermediates\res\debug -A C:\Users\Nooles\AndroidStudioProjects\maps\app\build\intermediates\assets\debug -m -J C:\Users\Nooles\AndroidStudioProjects\maps\app\build\generated\source\r\debug -F C:\Users\Nooles\AndroidStudioProjects\maps\app\build\intermediates\res\resources-debug.ap_ --debug-mode --custom-package com.twinandco.maps -0 apk --output-text-symbols C:\Users\Noodles\AndroidStudioProjects\maps\app\build\intermediates\symbols\debug Error Code: 1 Output: C:\Users\Nooles\AndroidStudioProjects\maps\app\build\intermediates\res\debug\menu\menu_main.xml:4: error: Error: No resource found that matches the given name (at 'title' with value '@string/action settings')"-

android:layout_width="fill_parent" android:orientation="vertical" android:layout_height="fill_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin">