Error initializing Cordova: Class not found

It is config.xml not configs.xml.

Based on the logs I'm seeing you are missing this file in your apps res/xml directory. It is included as part of the distribution at lib/android/res/xml/config.xml so copy that file into your res/xml directory and you should be all set.

Just as aharris88 in his answer to this question, I had the [CORDOVA] Error initilizing Cordova: Class not found error message when using Cordova 3.1.0 on my Android dev phone after migrating from Phonegap 3.0.

All fiddling with the config.xml file in the /platforms/android/res/xml directory did not help. Based on the Stackoverflow answer mentioned above, I tried to "start over" by reinstalling Android platform support:

cordova platform rm android
cordova platform add android

After this step it worked again, and I was able to cordova build android && cordova run android without any further problems.

I have had this error because of a plugin that I deleted. I Added

<plugin name="Device" value="org.apache.cordova.Device"/>

to the config.xml file again and it fixed it.

My you not have following plugin:

<plugin name="Device" value="org.apache.cordova.Device"/>

You have to put that in between <plugins></plugins>. like

<plugins>
    <plugin name="Device" value="org.apache.cordova.Device"/>
</plugins>