Personnel number not yet assigned

Hello Experts,

I've deployed and configured ESS and MSS Business packages successfully. From here, I've assigned the Employee Self Service Role to one of my test user. The ESS Role and its worksets are veru much visible.

But the problem starts for me when I try to access the links available in the Area Group Page like Who's Who, Record Working Time etc...

The error that's stoping me to proceed further is Critical Error. It also says Personnel number not yet assigned.

I've tried to follow different answered threads in this category, but nothing seems to solve my problem.

Could somebody with patience explain me the causes for this error and solutions to get rid of this?

Thanks a lot,

Balaji