Error while trying to initiate process as HR administrator

Dears,

When am trying to login to portal as HR administrator and when i try to Start a process through HR administrator tab for an employee, am getting the error

I checked both backend and portal role and initiator is having appropriate roles and the employee in screenshot belonging to the same group of the HR administrator. I checked this in table T526.

Can someone help me in finding what reason it could be?

Thanks a bunch in adv..

Regards,

Vignesh.