is it possible to issue goods using MB1A & Mvt 251 for the month of may'07

hi

i am trying to process idocs for the month of may'07 in the current month (july'07) and system says goods can not be issued in the month of may'07.

is it possible to issue goods using MB1A & Mvt 251 for the month of may'07 or any other method to process may'07 idocs now.

thanks & regards'

manoj gupta