Error while creating timesheet in Project

Hi All

While creating the timesheet in the project module i am getting the following error:

"Timesheet periods have not been created for:"

I checked the user is mapped with the worker, period type is defined on the worker form, periods are created.  Also when i click on new timesheet in the worker field drop down there is no worker showing. Also in the error after "for:" there is no worker ID. I am not getting what i missed in the setup, please advise

Thanks in advance