48"x48" poster PDF - graphics distorted

Good evening,

I'm having some minor difficulties tonight. Nothing that I can't handle via a workaround, but was wondering if anyone knew why some InDesign elements are getting distorted in my PDFs.

Here's the process I'm going through:

I'm working on a 48"x48" poster that includes a logo, some text and some multi-angled shapes that I drew with the pen tool in InDesign on a blank background. The shapes extend from the very top edge down to the very bottom edge.

When I look at the PDF that I generate, however, the shapes that I drew in InDesign have been squashed to about 2/3 their true height (it's not just missing the bottom third -- the shapes are actually distorted, the bottom of the shapes being pulled up and the angles adjusted accordingly).

And, to go over my PostScript file generation process:

I have a Print Preset in InDesign that I use to create a PostScript file, which I then drag to Distiller, which is set to the PDF/X-1A:2001 setting.

My Print Preset for generating the PostScript file includes the following settings:

Printer: PostScript File
PPD: AdobePDF 8.0
Paper Size: Custom (which automatically sets the size of the PDF to my document size)
Marks/Bleeds: (all off)

Is there something I'm missing? Is it just due to the 48" size of the InDesign document (I've saved a separate, half-size version of the InDesign file and created a PDF of that one and it looks fine)?

I've tried exporting the page as an EPS, resaving from Illustrator, dragging that EPS to Distiller to create a new PDF (same issue) as well as placing that EPS back into InDesign and re-creating the PDF (same issue).

The only thing that makes the PDF look correct is setting the InDesign file to a percent scale of the actual size ... or doing a standard Export and selecting Adobe PDF from the drop-down list (which can create unreliable files that may look fine on-screen but then print incorrectly, so I typically don't use this method).

One other note: on a separate test file I created, I added a black fill to the background of a 48"x48" InDesign file, drew a similar multi-angled shape on top of it in another color, used my normal PostScript file-to-Distiller method of creating a PDF, and the black actually filled the canvas in the PDF, but this new multi-angle shape was, again, distorted.

Any thoughts on why this might be happening?

Thanks!

Oops, forgot my versions:

InDesign CS2
Acrobat Professional 8.1.2

Mac OS X 10.4.11