Need some help with saving config

Hey,
I recently noticed that my Referrals plugin, on reloads, is no longer saving the int key for how many referrals a player has on reloads. I don't know why this is happening, it was working fine a bit ago.
I should also note there is NPE's on line 46 and 72. Just haven't bothered to fix them yet because it was working still, even with those errors. (Though now its not)
http://pastebin.com/C3eVeMZF
Here is an example of what the config looks like

Code:

refers:
  pumpberry: 2
  pumpmelon: {}
never:
  pumpmelon: never.pumpmelon
  pumpberry: never.pumpberry

Thanks for your help!

 

Code:

this.config.getConfigurationSection("refers").getKeys(true);

whats the point of this? Also, check if refers is set using .isSet to prevent NPES. The reason why theres and npe on line 72 is because its calling the loadconfig method, which is where line 42s npe is. Instead of making a yaml file for the config use getConfig or this.getConfig