no installed build tools found. install the android build tools version 19.1.0 or higher.
You need to write the correct "Environment Variables". See: https://developer.android.com/studio/command-line/variables
Windows:
setx ANDROID_SDK_ROOT "C:\android-sdk-windows"
setx PATH "%PATH%;%ANDROID_SDK_ROOT%\tools;%ANDROID_SDK_ROOT%\platform-tools"
Mac OS X
export ANDROID_SDK_ROOT=/<installation location>/android-sdk-macosx
export PATH=${PATH}:$ANDROID_SDK_ROOT/tools:$ANDROID_SDK_ROOT/platform-tools
Linux
export ANDROID_SDK_ROOT=/<installation location>/android-sdk-linux
export PATH=${PATH}:$ANDROID_SDK_ROOT/tools:$ANDROID_SDK_ROOT/platform-tools
Update: ANDROID_HOME is deprecated, ANDROID_SDK_ROOT is now the correct variable