getting an error in trigger while invoking a procedure in it

i have created a procedure name 'prd' which contains 3 parameters(pmat_amt,pstartdate,pstopdate) which is used to update a column in the table 'rd_details' contains 3 columns which are mat_amt,startdate,stopdate.. later on i have created one trigger which was.. create trigger rd_trig after update of stopdate on rd_details for each row begin prd(:new.mat_amt,:new.:new.startdate,:new.stopdate); end; /

but i'm getting an error as :bad bind variable :new.mat_amt :bad bind variable :new.startdate :bad bind variable :new.stopdate