I just had the Oracle Installer complaining that it cannot install the 10.0.1.3 patchset as an "ocssd.bin" process is still running in the background. The quick solution was to kill this process and continue the installation.
A more permanent fix is to comment out the following line in /etc/inittab and reboot the
h1:35:respawn:/etc/init.d/init.cssd run >/dev/null 2>&1
For some reason even though you may not use RAC or ASM, OCSSD (Oracle Cluster Synchronization Service Daemon) is installed regardless if it's being used or not.