I got the same problem using the latest public patreon version of the renpy plugin (8.1.1_7.6.1_000). Try grabbing the previous public version from patreon (8.0.3_7.5.3_010). That fixed it for me.
You don't neccessarily have to downgrade the renpy plugin. You could also longclick/hold the game icon in joiplay, unpack archives, go to the game/images folder and delete the "@" from the image that appears in the error since the "@" seems to be what is causing the problem. If you do that it probably won't load in-game though.