K2 establishes their general guidelines for environment and application software support in their K2 blackpearl 4.6 Compatibility Matrix, under their Microsoft Product Support Plan.
A user is unable to open the InfoPath form associated with a workflow task. The exception reads:
You have insufficient rights to access the task. Ensure that you have contribute rights on the site before attempting to open the task.
It’s a SharePoint permissions problem. Fortunately, it’s an easy fix.