You cannot use the yum utility to do a major version upgrade, such as upgrading from Oracle Linux 5 to Oracle Linux 6. Kernel version 2.6.32-358.el6 is the RHCK kernel and requires Oracle Linux 6. So if your attempt was to install a driver that works only for the Red Hat Enterprise Linux 6 kernel, you will have to upgrade the OS first. For this you must start from the OL6 installation DVD, but upgrading between major release versions is not officially supported. You can however upgrade to the latest Oracle UEK kernel, by enabling the appropriate channel in the yum repository configuration file.