Thanks.
The problem still remain.
I'm using this code in a function, that running each time I wish to insert a new control. The MainFrame is the first control that I'm inserting and it the container of the following label controls that I want to add but when it get to the 'Else' it giving me the error:"Invalid object use".
What can I do to solve it?

Dim MyControl As Control
Set MyControl = Form.Controls.Add(ControlType, ControlName, Form)
Static y As Control
If MyControl.Name = "MainFrame" Then
Set y = MyControl
Else
Set MyControl.Container = y
End If