outlook 2003 custom form

i designed a custom form in outlook 2003. this form is used for fixing appointment with the usergroup. it can be maintained with a VB application also.
i am getting problems in opening a previously fixed appointment in order to view or update data on it.the VB Script code written for functioning this custom form is not working at all while opening a previously fixed appointment. everything is very fine with a new appointment form( no matter it is fixed by VB application or by outlook user).....but in case of a previously fixed appointment.....Script is not running at all.....please help....i am not getiing any idea what is happening.....