Need help with a VBA msg box

I have on the close event this code

my form is simply a form for the user to enter the date they are going to be working with. I then append that date to a another and drive the rest of my reports off that date. The reason im using the gotorecord , , acnext is without telling access "im done with this record move to the next" it doesn't record the date. The issue im having is if the user decided to open the database and then just close access without entering the date they get the debug screen. I'd like for a msgbox to open saying No Date Entered and once they hit okay it goes back to my form and if they hit cancel it closes the DB. Any help would be greatly appreciated.