UT theoretical chemistry code forum

I have been running dimer calculations for TS for a while now.
However, recently I encountered the error " Error reading item 'PERTPOTS' from INCAR" while running on a new machine.I am unable to find any documentation on this tag also. Any ideas why this error is coming up?

Thanks in advance!

I don't see any reference to PERTPOTS in our code, or the vasp code. So this is a mystery.