If you get an error installing the plugin, you should now get an error saying you either need Vault installed, or if you need an Economy plugin (like EssentialsX).
I tested the error everyone was having and aside from the plugin not being able to run on 1.17.1 servers, I've discovered that what was actually happening was people were installing AnCasino without a plugin with a /money or /balance command, I didn't put it as a soft defend because AnCasino doesn't care which one you use as long as it has some sort of economy. So a huge pink error in the console should appear if you do NOT have both Vault and/or an Economy plugin (like EssentialsX), I hope that sheds some light as I got it working again on 1.17.1!