An interesting issue.

OES 2 SP4, Novell Open Enterprise Server 2.0.3 (x86_64), VERSION = 2.0.3, PATCHLEVEL = 3

Everything is working as expected as far as mappings and file resources. I can double click and any file and it will open. Openoffice file in open office, a jpg in a graphics editor. However, If I select and download the file, the file size is only a few bytes. Normally about 238B.

I double clicked an spreadsheet, the browser didn't know what to do with it, so gave me the save dialog. I save the file and then opened it ALL OKAY.
I select the same file using the tick box, choose File Download, save it to the exact location (changing the saved filename) and the file is corrupt.
Any file type does the same thing.

If you select a bunch of files and download the zip, the ZIP is okay, by the files it contains are only 238B on average.
A tiny text file that is smaller than this in size is readable. It's like files are being truncated when the FIle Download action is used.

We are using SSL and a basic reverse proxy access gateway service (Novell Access Manager 3.1.3-273) to publish the system. As long as you don't want to download a file, and simply view files by double clicking on them, all works fine.
You get the same results for Windows firefox 16.02 and Chrome Version 23.0.1271.64 m. ALl my Linux browsers do the same thing.

Does anyone have any ideas?