I haven’t used the command in a while, so I’m not sure if this is a new problem. When selecting the Planar Lips command in R6, (6.0.18002.10461, 01/02/2018), from Paneling tools->Paneling Utility, it says “Unknown command _ptPlanarLips”.
I am using paneling tools version: Nov 13, 2017.
EDIT: I just noticed that the “new to me” command is ptTabs.