The listener would still have the ProjectKorra.plugin for the runnable task. I would recommend using BukkitRunnables() for any tasks that you are going to do.
//In the Listener class and more specifically inside a method
BukkitRunnable br = new BukkitRunnable(){
public void run(){
// Your Code Goes here.
// For Example
Bukkit.broadcastMessage("This event happened 2 seconds ago.");
}
}
long delay = 40; // In ticks, so 20 ticks to the second.
br.runTaskDelay(ProjectKorra.plugin, delay);
The ProjectKorra.plugin part is always going to be there no matter which file you put it in.