payslip error

Hi

i m not getting the take home pay in the salary slip

Lets say when i m putting 01/02/2008 in pc00_m40_calc

i ve to get only April month salary slip.but in stead of getting only April month salary slip i m getting from the joining date of the employee.

let the employee DoJ is 05/05/2007 then i m getting from 05/05/2007 till April.

and in that salary slip i am not getting take home pay.

Pls suggest.

Thanks