I tied that. The same thing. I just can't cast it into my interface:

Code:
 Dim tArr As Type() = asm.GetExportedTypes


        For Each t As Type In tArr
            If t.GetInterface("IPluginInterface") IsNot Nothing Then
                Dim o As Object = asm.CreateInstance(t.FullName)

                If o IsNot Nothing Then
                    CType(o, IPluginInterface).DoWork() ' InvalidCastException
                End If
            End If
        Next