Did you happen to see this guide?
https://docs.unrealengine.com/latest/INT/Platforms/Android/GettingStarted/1/index.html
The part you care about is installing the SDK. If you already have ant installed then you can look into this page:
The key line in your log is here:
LogPlayLevel: Program.Main: ERROR: ERROR: Unable to find ant.bat (via %ANT_HOME% or %ANDROID_HOME%/…/eclipse/plugins/org.apache.ant*
You need to have your environment variable specified correctly for ant… ANT_HOME is what you want