I'm using the same versions as you are, Sencha Touch 2.3.0 and Sencha Cmd 220.127.116.11.
PS: make sure to use the correct.apk file.
If your packager.json points to "outputPath":"../build/" make sure you take the right build directory (since the sencha app package build packager.json command creates a different build directory).
Thanks for the update. Ext.application should have Main listed in its view config by default. Do you have 2 main views? Possibly the default MyApp.view.Main and the MyCPA.view.Main? Did you edit the existing Main.js?