2.6.0.7 Premium Upgrade Fails

Hey guys,

My client went and clicked the beta update, which is fine because it has some really nice features. Unfortunately, now when I attempt her premium upgrade the following error occurs:

file has not been recognised /path/to/client/public_html/wp-content/plugins/wysija-newsletters/helpers/package.php
WYSIJA_help_package
helper

Should I roll back or can I fix the error? Beta used to work just fine before we disabled it on a support ticket.

https://www.ads-software.com/plugins/wysija-newsletters/