It sounds to me like Oracle.dll cannot load because it cannot find your real (non-perl) Oracle libraries. You probably need to add $ORACLE_HOME to the script that starts Apache. Your httpd error_log should say something to that effect if this is the problem. If you're running mod_perl, you'll probably need the following somewhere in your httpd.conf file as well:
I did fail to mention that the Oracle client I installed on this box is version 10g. Have you heard of any issues with 10g? I will try your recommendation. Thanks!