accdr extension....

Hello all,
I have Access 2007, and most of the users have 2003. I saved the
database as a .accdr file extension that lock the ribbon and pane; but when
an user with 2003 opens it, he or she is able to see the whole pane and
ribbon on the window. In other words, .accdr works for 2007 but not for 2003.
any way to make this works.

NOTE: The file is 2003 format so everyone could use it.