#Deleted Error

I have a split database, that 3 people utilized... one of the fields (called
Updates) is a memo field, where we can mantain notes on an account. I am not
sure if two people had the same record open at the same time (but I believe
this to be the case), and each tried to modify the record, specifically the
Updates field, but now we have #Deleted instead of the notes. I went to the
back-up and copied the notes, but the #Deleted won't let me paste the notes
back into the field.

I have read another posting where it says: Set your form's Allow Deletions
property to NO if they aren't supposed to be able to delete records. (data
tab of form properties), but do you do this for the field itself or do you
set the properties for the form itself? How will this effect things?

Should I have set something else when I split the database to make sure no
two people could change a record at the same time?

Any suggestions would be Greatly Apprecitated!
Maura