SIS - problem in info structure

Dear all

i have configured all the setting for SIS but when i create Sales order, the system is showing the message that -

"Error determining posting period (Info structure S014, variant C1, Rc 3)"

when i click on help it is showing following infomation

Diagnosis

Exception 3 occurred when function module PERIOD_DETERMINE was called

the system is not allowing me to save the sales order. moreover i am not able to change the info structure also.

pls help

regrds