I just wanted to follow up in case anyone else encounters a similar environment. We installed the 64-bit Oracle 11g client and it came with the 32-bit libraries in the "lib32" directory. Following instructions in the DBD:Oracle readme, we added the Oracle Client's "lib32" directory to the LD_LIBRARY_PATH. We were then able to make and install the DBD:Oracle module. The "make test" process failed miserably due to some sort of Testing module issue, but a test connection worked. If I encounter more issues, I'll follow up, otherwise it worked fine.