Getting ACR.UserDialogs samples to work on Android

I am trying to use ACR.UserDialogs and I'm getting an error. I tried the sample in ACR.UserDialogs and am getting the same error.
If I use Samples.Droid everything works fine.
But if I use Samples.Droid.Classic, use nuget to get the 4.2 versions of ACR.UserDialogs, and then try to show an Action Sheet I get:

'Android.Content.Res.Resources+NotFoundException: Resource ID #0x0'

when calling 'UserDialogs.Instance.ActionSheet(cfg)'

This is also the same error I'm seeing in my code. I can't really tell the difference between Samples.Droid and Samples.Droid.Classic. Classic derives from FormsApplicationActivity (the same as my app) and the other derives from FormsAppCompatActivity

Any idea what I might be missing, or what the issue is?