I just installed JComments with this same set-up, K2 on RocketTheme Affinity template. I have enabled the latest JComments K2 plugin. The problem is when I try and load a K2 article I get the following errors:
Warning: Invalid argument supplied for foreach() in /root/templates/rt_affinity_j15/html/com_k2/templates/default/item.php on line 518
Fatal error: Call to a member function getPagesLinks() on a non-object in root/templates/rt_affinity_j15/html/com_k2/templates/default/item.php on line 558