May 15, 2004 - You should simply try patching your server per tip #1 here and try my proxy.cfg file from tip #63 here.
Properly patched servers using my proxy.cfg file should never have the issue viewing PDF files.
Here are some tips from Novell if you are having problems viewing PDF files in your browser through HTTP Proxy.
Because the HTTP proxy does not support HTTP range headers, it is difficult to view PDF files through the Netscape browser. This issue requires the user to use the reload button
frequently, but only occurs with version 4.05c of the Acrobat plug-in. Update to Acrobat version 5.0 to solve it.
To enable viewing of PDF files through the Netscape browser, implement the following changes to the ETC/PROXY/PROXY.CFG file:
[Extra Configuration]
DiscardAcceptRanges=1
If Microsoft Internet Explorer (IE) 5.x is unable to open PDF (Adobe Acrobat) files, implement the following change in the ETC/PROXY/PROXY.CFG file:
[Extra Configuration]
PassContentLength=1
Note: Sometimes you need to specify the setting even if you are calling out what should be the default value.
These settings apply to BorderManager 3.5 and later. Be sure to check your patches against TIP #1 here.