In PCLinuxOS has no ros session packages, but Open Mandriva packages are working with PCLinuxOS. Install the next packages

rox-2.10-3-omv4000.x86_64.rpm
rox-session-0.30-7-omv4002.noarch.rpm
rox-lib-2.0.6-2-omv4002.noarch.rpm

You can find them from
https://pkgs.org/search/?q=rox-session

These packages are in my PCLinuxOS

You need to install IceWM also and then add rox-session to the .icewm/startup file. My startup file looks like

#!/bin/sh
##idesk &
redshift &
conky &
nm-applet &
rox-session &