The conflict's not with the aD Oracle driver, but with Oracle, which includes its own ldap library. Oscar mentions this on his web page.
The note you refer to does mention that the person hacked together an ldap extention to AOLserver but it doesn't mention him releasing it. Or documenting it. Or anything like that.
The aD acs-ldap-authentication package relies on Oracle's embedded ldap capabilities. Not terribly useful for OpenACS 4. Think Postgres. Think future RDBMSs we might want to support. Oscar may want to use this as a starting point, replacing the Oracle dependencies with calls to nsldap. I've looked at the package and it's a hack, though.
An LDAP authentication package for OpenACS 4 that doesn't require Oracle would be welcome by some folks. I have no doubt of that.
