Need help enabling themes on Irssi 1.4.5 (UbuntuMATE)

Themes won't work on Irssi 1.4.5. I've downloaded the theme files into the correct directories but they do not work. I have checked the custom themes and they do have code inside them, so that isn't the problem. Even the preinstalled ones that come with installing Irssi itself don't work (excluding default). My suspicions are either I accidentally installed it incorrectly, or themes are incompatible with my distribution (I hope it's not the latter). I have Meson 0.49.0 but couldn't install Ninja 1.5 and had to use 1.5.1 since 1.5 was not on the Ninja Github page.

PS. If there's no help for this issue here, where's a better place to ask? I would ask on Irssi itself but I'm familiar with tech support forums and find that more efficient. Is there an Irssi forum I don't know about?
Attached Thumbnails