Trouble migrating Sencha2.4+Phonegap project

I followed the official migration guide to migrate our Phonegap (with Cordova) project. It uses an older version of Sencha (2.4). After following the guide I was able to build the native binaries for Android.

When I start the app, I am stuck within the loading screen. The log shows the following error message: “E/AndroidProtocolHandler: Unable to open asset URL: file:///android_asset/www/.sencha/app/microloader/development.js”

I tried to get it done by creating a new Sencha project, integrating our source step by step. I thought that reorganizing the app to follow the migration guide (sources within www-folder) created these issues. But the same error occurs.

Maybe someone faced these issues aswell. Again, it is a fairly old project, written with old libraries. Here is my current project structure: