Can't find /lib/libz.so.1

Project:PDF Include project
Component:Code
Category:support request
Priority:critical
Assigned:Unassigned
Status:active
Description

OS: HP-UX
PROGRESS: 9.1D
ZLIB: 1.2.3

I am trying to import an existing pdf using pdf include, and I get the following error.

Could not open Dynamic Library: /lib/libz.so.1 (8013) Could not load DLL procedure /lib/libz.so.1. (3258)

I am running it at root, and the file does not exist. I did a find to look for libz.so.1 anywhere on the system, and it isn't there. ZLIB is installed.

I know that the other features (such as writing text, and importing an image and placing it) on pdfinclude works fine.

Your help is MUCH APPRECIATED.