We were able to find a workaround for the TNS lookup problem (see my reply downstream). However, with regard to your question-- no, there is no other version of Oracle installed on the server and we did compile with Oracle10 libraries.
From what I was able to find through research, the Oracle8 driver name is pretty much arbitrary and does not influence what database version the driver actually looks for. I did read that previous versions of AOLServer are picky about the driver name and the name of the nsoracle file itself, but that version 4.5 is not.
