Coursepress Pro Giving Error in Preview, Putting Units in Draft Mode

I've been getting an error that I had asked about on a clients account for a different site, so this isn't just one site, I've experiencing this issue across multiple sites. When a unit is in draft mode, if I go to view it, I get an error and can not view the preview unless I change it to live mode. Also, I have noticed when I do have a unit in draft mode (since it shouldn't be released yet) if I go to look at any other unit that is currently live, it will change that unit to draft mode. A third issue with COursepress pro is that from the front end I am unable to go back and look at the content in past units if I have already looked at that unit. I have support enabled for the website. We have been having numerous issues with Coursepress Pro and again, this is not just on this site but on other client sites, the above issues I am having on 2 other sites as well.