We'll have to look into why those notices are appearing more on our side. However, those are simply 'Notices', not warnings or errors and shouldn't prevent normal functionality. Basically, those are messages from PHP to 'us', the developers, that something's not perfect, but not is really wrong.
From a quick look at our code, the automatic Like/Comment boxes that can be configured to show in your content is triggering on those pages. I'm not sure why that would be, but since it's a Virtuemart page, and not Joomla or K2 content, our plugin isn't finding the information it wants to see (category id, for example).
Are you using Virtuemart2 to display on those pages, or are you using some other extension that works with Virtuemart to display them?
In the meantime, I'd recommend going into the Global Configuration area of Joomla and setting "Error Reporting" to "None", which will hide those notices.
Hope that helps,
Alex
Undefined property notices
