I think this is caused by having multiple onloads in the body tag.
try using this for the body tag:
<body onload="<? if (isset($_GET['ID'])) { ?> WA_setSelectionsInChildList(MM_findObj('orgID'),<?php echo $row_project['agency']; ?>);<? } ?><? if (isset($row_project['agency'])) { ?>WA_FilterAndPopulateSubList(contacts_WAJA,MM_findObj(<? echo $row_project['agency']; ?>),MM_findObj('contact'),1,0,false,': ');WA_setSelectionsInChildList(MM_findObj('contact'),<?php echo $row_project['contact']; ?>) <? } ?>">