If you are not having
CustomPlayerSkins plugin installed, you will get this error if
sm_csgo_adminesp_mode set to
1. Set value to 0 in plugin's config to avoid this error (however all players will be red colored). If u want colored - install plugin and set value to 1, obviously.
Mitchell btw as far as I know you havent updated .smx file on github. I cant check github yet because its banned in Russia at the moment and tor browser != working :E