System Error while opening Timesheet through Portal

Hi Experts,

I am getting the below error message while opening the timesheet through Web Portal. But I am not getting any error if I book time through back end i.e. CAT2 Transaction.

System error: No receiver could be determined

This error comes in Portal only (not in backend) once I enable "HR Enables CATS" option in Data entry profile through CAC1 transaction. There is no error if the same option is disabled. But we need this option to be enabled.

Can anybody help me ASAP for the same?

Thanks,

Atin