Android : error when building android sample games in android studio

i downloaded the android sample games and imported them on my android studio however i keep getting an errors![enter image description here][1] Error:Error: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Users\soko\AppData\Local\Android\android-sdk\build-tools\20.0.0\aapt.exe'' finished with non-zero exit value 42

Error:Execution failed for task ':SkeletonTbmp:mergeDebugResources'.

C:\Users\soko\Downloads\Compressed\android-basic-samples-master\android-basic-samples-master\BasicSamples\SkeletonTbmp\build\intermediates\exploded-aar\com.android.support\appcompat-v7\20.0.0\res\drawable-xhdpi\abc_textfield_search_right_selected_holo_light.9.png: Error: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Users\soko\AppData\Local\Android\android-sdk\build-tools\20.0.0\aapt.exe'' finished with non-zero exit value 42