Hi golauty,
Welcome to VC.
I have no idea what this could be yet, but that little snippet of the log is not enough to get an idea of what is happening. I always encourage people to attach the complete log file to their posts. In this case an XBMC log would help too. Even then it is quite possible that we won't be able to really see what is happening, especially since VC is obviously getting caught off guard by something. Maybe XBMC is disappearing in the middle of a conversation.
In the steam addon settings try telling it not to close XBMC and see if that solves the problem.
Another thing you could try would be to disable the connection from VC to XBMC which monitors for notifications (like new track playing etc.). To do that you would need to need to go to your VC xJson plugin settings and make sure that "subscribe to notifications" is unchecked. You also need to delete the command in your tree which auto-connects whenever XBMC gets focus.