Tom:
I was able to create this with a door panel, using minimum sash dimensions and the H-V grid with 30 Horizontal Panels and 1 Vertical Panel. Or you could remove the panel and place Louver object in the opening.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David