Works fine for single approvers, explicitly listing 2 users is fine, but adding a role, AD Group or sharepoint group generates this error when you go to edit the task:-
There
has been a problem retrieving the K2 process data. Please ensure that the
account has rights to the K2 Workflow Item and that you are connecting to the K2
server.
server is 64bit, same as sharepoint (MOSS) server and sql server (evaluating K2). using K2 studio on a client machine.
App pool owner is a domain account.