You can set password by using NewPassword method.

If you want to open MDB file with the password,
you must specify password in Connect property for Data control or in
4th argument of OpenDatabase method for DAO.

For example, if you are using Data control,

Data1.Database.Connect = ";PWD=password_string"

For more information, read on-line help.

I think when you redefine the recordset of Data control, there is a control
that is bounded to field which is not in new recordset.

check bound control's DataField property.