accounting document status not cleared??????

hi experts,

I have done invoice VF01 AND j1IIN SALES .WHEN DOING j1i5 - rg1 REGISTER .WHILE SIMULATING ALL OTHERS GET UPDATED ONLY FOR 1 ENTRY IT IS SHOWING ERROR MESSAGE ....WHEN I CHECKED DOCUMENT FLOW ACCOUNT ASSIGNMENT STATUS IS UNCLEARED ..FOR THAT DOCUMENT ALONE .WHAT MAY BE THE REASON...

MANI