$connector should be $con in line 473 of /lib/rule-classes/NatRule.php

$connector was apparently renamed at some point and this got missed?

Line 473 in 69d70a9

    
           $connector->sendEditRequest($xpath, DH::dom_to_xml($this->dnatroot, -1, FALSE), TRUE);

As I do not have access anymore to this repository since October 2023;
This bug was already fixed in November 2023 and is available and maintained in the following repository:

https://github.com/swaschkut/pan-os-php

Which is of course also available in the same docker repository as before:
docker run --name panosphp --rm -v ${PWD}:/share -it swaschkut/pan-os-php:latest