Form access error when try to use a Form from Project1 in Project2

I have two project in same solution, where I try to use a form from the other project in this project.

I have added Project1 as en reference in Project2 (Reference to the exe file - Correct? )

And then I try this in a mdicontainer form i Project2:

        Dim ReportFrm As New Project1.Form_report

        ReportFrm.Close()
        ReportFrm.MdiParent = Me
        ReportFrm.WindowState = FormWindowState.Maximized
        ReportFrm.Show()

Then I get this error when try "ReportFrm.Show()" : exception: can't access removed object

What to do ?