This is odd. The only difference I can see between the two posted dbs is the ControlSource properties are bound to fields in the second. Never encountered this before and I don't know why it is happening.
But why are you using ValueList instead of Table as source for the lists? For example, settings for Employee combobox:
RowSourceType: Table/Query
RowSource: SELECT EmployeeID, LastName & ", " & FirstName AS FullName FROM Employees ORDER BY LastName, FirstName;
ControlSource: EmployeeID
BoundColumn: 1
ColumnCount: 2
ColumnWidths: 0";1"
LimitToList: Yes