Unable to Checkout (warning remote head refers to nonexistent ref)

Hello,

I'm very interested in your module as there doesn't seem to be any other functionality similar to it. I find it strange too because displaying and filtering by available attributes seems like something that's common to most e-commerce sites.

Unfortunately, I'm unable to test the package since there seems to be something wrong with the way it was published:

This is the warning I'm getting:
warning remote head refers to nonexistent ref

The issue and solution seem to be described here:
http://stackoverflow.com/questions/1961274/git-warning-remote-head-refer...

Thanks in advance for your help!

Danny