I downloaded the plugin and installed it using Pluginman. It works perfectly. Then, I added the permission to the moderators (echopet.pet.*) and it doesn't work. I am using EchoPet v2.8.0 and Craftbukkit 1.8. Please help me, thanks!

The permissions are working fine.
Don't use plugman, restart your server...
Currently the jenkins for dev builds ist offline when it's online again, but you should use Echopet Build 67 with spigot/craftbukkit 1.8.8