Trouble Installing PEAR from Source, can't find libclntsh.dylib.10.1

I was asked to look over a laptop (OS X, 10.5) that was setup for a new developer, and I discovered that the pear executable was missing. This shop sets PHP up from source, so I navigated to the source tree where they'd compiled things and tried a make install, which failed with

Installing PEAR environment:      /usr/local/lib/php/
dyld: Library not loaded: /b/32_216/rdbms/lib/libclntsh.dylib.10.1
  Referenced from: /Users/username/Source/php-5.2.8/sapi/cli/php
  Reason: image not found
make[1]: *** [install-pear-installer] Trace/BPT trap
make: *** [install-pear] Error 2

So I tried a configure/make clean/make/make install, and hit the same problem.

All of these commands were run with sudo, as the source tree was owned by root.

I tracked the problem down to this command with make -n install-pear

sudo /Users/username/Source/php-5.2.8/sapi/cli/php -n -dshort_open_tag=0 -dsafe_mode=0 -dopen_basedir= -derror_reporting=E_ALL -dmemory_limit=-1 -ddetect_unicode=0 pear/install-pear-no    zlib.phar -d "/usr/local/lib/php" -b "/usr/local/bin"-dshort_open_tag=0 -dsafe_mode=0 -dopen_basedir= -derror_reporting=E_ALL -dmemory_limit=-1 -ddetec
Installing PEAR environment:      /usr/local/lib/php/
dyld: Library not loaded: /b/32_216/rdbms/lib/libclntsh.dylib.10.1
  Referenced from: /Users/username/Source/php-5.2.8/sapi/cli/php
  Reason: image not found
make[1]: *** [install-pear-installer] Trace/BPT trap
make: *** [install-pear] Error 2

What's strange, and possibly a red herring, is when I run the command as a non-root user, I seem to get further in the process

Installing PEAR environment:      /usr/local/lib/php/
[PEAR] Console_Getopt: failed to mkdir /usr/local/lib/php/Console
[PEAR] Archive_Tar: failed to mkdir /usr/local/lib/php/Archive
[PEAR] Structures_Graph: failed to mkdir /usr/local/lib/php/doc/Structures_Graph/docs/html/media
warning: pear/PEAR requires package "pear/Archive_Tar" (recommended version 1.3.2)
warning: pear/PEAR requires package "pear/Structures_Graph" (recommended version 1.0.2)
warning: pear/PEAR requires package "pear/Console_Getopt" (recommended version 1.2.3)
pear/PEAR can optionally use package "pear/XML_RPC" (version >= 1.4.0)
[PEAR] PEAR: failed to mkdir /usr/local/lib/php/OS

(Although it may be that when running as sudo those commands just run silently when they're successful.)

I thought it this might be a $PATH problem when running as sudo, but it seems like everything is similar there.

$ sudo echo $PATH
/usr/local/bin:/sw/bin:/sw/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/X11R6/bin:/usr/local/instantclient

$ echo $PATH
/usr/local/bin:/sw/bin:/sw/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/X11R6/bin:/usr/local/instantclient

The /usr/local/instantclient folder is where the missing library is located.

I'm at a bit of a loss as to the next "what do I check" steps are, and was hoping the ServerFault might be able to help me before I punt back to the IT folks.