I don't know, if this example will work, but I just think, that example from Wiki page is a little bit overcomplicated. Try to do this:
1) Create library
2) Add form to in via File->Create form
3) Edit form's design and code
4) All you need - is just one function, exported from Dll: function CreateMyForm:TFormClass;begin Result := TMyForm; end;
5) Then just try to do Application.CreateFrom(<Result of CreateMyFrom from Dll>, MyForm).
P.S. I tried to do it. Everything works. CreateMyForm is called. Form is created. But when I call MyForm.Show - nothing happens.
P.P.S. TForm meta classes differ - "Instance is TForm" doesn't work.
P.P.P.S. Attached project seems to work!
If project works on Win32, but doesn't on Win64, it usually means, that it has invalid pointer casting somewhere. And many copies of RTL and VLC in every DLL - is real reason, why we need runtime packages.