Hey there.
Sorry about that. When I was in the process of making the changes in the plugin, I used 'actor' as a stand in for 'this._actor'. Then I went through and changed it to what it was supposed to be... in everything except yanfly's equip scene, I believe. I'm not sure how that slipped by me, but it's been fixed and is available in revision a, which you can download from the plugin page.
As for the load order fixing it, if you have the monkeygrip plugin, it should be loaded after the menu extension, as it adds on to some of the functions that draw menu modifications, and it needs to load after those scenes. Additionally the menu extension should be loaded after the YEP menus that it modifies (equip, shop, status, party system, class change). If you don't load it after these, some of the menus will probably look a bit funky.