I would you following scenario...
var FName
var MName
var LName
FName = form1.subformname.FirstName.rawValue
MName = form1.subformname.MidName.rawValue
LName = form1.subformname.LastName.rawValue
form1.subformname.FullName.rawValue = Concat(LName, ", ", FName, " ", MName)
I will use this FormCalc code in 'exit' event of each of the name fields.
In your case make sure the syntax and check for typos.
Good luck,
SekharN,
www.lawson.com