I too am getting this same error message.

Your server is unable to create a session necessary for AbanteCart functionality.

 I have a new installation at Godaddy on a cpanel linux system.  Abantecart seems to be working just fine.  When contacting their support I get the same response, this is an application issue.

How do I determine if this is causing issues with the installation?  As I mentioned I have yet to run into an issue where something is not working.