MoPub Unity NoClassDefFoundError

Hi,

I have been trying to implement the MoPub plugin to my Android Unity Project and I followed the instructions from here:

https://github.com/mopub/mopub-unity-android-plugin

But for some reason the app crashed because of the following error:

The class mentioned is in the Eclipse project.

I did rename the main to main_ to avoid the "Cannot nest 'mopub-sdk/src/main/java' inside mopub-sdk/src". To enable the nesting exclude ',ain/' from 'mopub-sdk/src'" error at Eclipse.

Could someone kindly tell me what's wrong?

I hope it is not a stupid question, I am not very familiar with Eclipse...

Thanks!