Error - failed to re-package resources (Android)

Hello all,

I've been creating a Android app / game, and it's been working great, but last night I got this error, when I tried to "Build & Run" so that I could test it on my phone It said "failed to re-package resources"

This is my console, and I've tried to look at it to locate the error, but with no luck, hopefully someone else have had the same problem and know a fix.

CONSOLE :

 Error building Player: CommandInvokationFailure: Failed to re-package resources. See the Console for details.
 C:\Users\xAIMx\AppData\Local\Android\android-sdk\build-tools\20.0.0\aapt.exe package --auto-add-overlay -v -f -m -J gen -M AndroidManifest.xml -S "res" -I "C:/Users/xAIMx/AppData/Local/Android/android-sdk/platforms/android-20\android.jar" -F bin/resources.ap_
 
 stderr[
 AndroidManifest.xml:9: error: Error: No resource found that matches the given name (at 'value' with value '@integer/google_play_services_version').
 ]
 stdout[
 Configurations:
  (default)
 
 Files:
   drawable\app_icon.png
     Src: () res\drawable\app_icon.png
   values\strings.xml
     Src: () res\values\strings.xml
   AndroidManifest.xml
     Src: () AndroidManifest.xml
 
 Resource Dirs:
   Type drawable
     drawable\app_icon.png
       Src: () res\drawable\app_icon.png
   Type values
     values\strings.xml
       Src: () res\values\strings.xml
 Including resources from package: C:\Users\xAIMx\AppData\Local\Android\android-sdk\platforms\android-20\android.jar
 applyFileOverlay for drawable
 applyFileOverlay for layout
 applyFileOverlay for anim
 applyFileOverlay for animator
 applyFileOverlay for interpolator
 applyFileOverlay for transition
 applyFileOverlay for xml
 applyFileOverlay for raw
 applyFileOverlay for color
 applyFileOverlay for menu
 applyFileOverlay for mipmap
 Processing image: res\drawable\app_icon.png
     (processed image res\drawable\app_icon.png: 94% size of source)
     (new resource id app_icon from drawable\app_icon.png #generated)
 ]