Solved 'An internal error occurred while attempting to perform this command' error

When i try to use the command from the plugin i just made and i don't have permission to use it i get the error in the in-game chat: 'An internal error occurred while attempting to perform this command' and in the console this is the error: https://pastebin.com/QJSabdqd As i said, this only happens when i don't have permission, with permission it works as it should.
Classes:
View attachment 31355 And another one:
View attachment 31356

 

Well that would explain it but i have it right here:
View attachment 31357

 

Oh, it needs to be capitalized the same aswell? Whoops mb then. Anyway, i'm new to this so uhm.. What is IDE and where do i find the plugins folder?
EDIT: Oh, you meant the config in the plugins folder on the server? If so then there is no folder with the plugin name for some reason. Did i forget something? If so then why is there no errors in the plugin?
EDIT 2: When i changed the capitalization it seemed to work but now i have a problem where it says that i don't have permission(which is what i want) but it also tells me the usage of the command from the plugin.yml for some reason. :/

 

Oh yeah, right mb again. Anyway, do you know why i don't have a folder for my plugin? (The folder where a config normally is)

 

Whoops i forgot.
Here it is:
View attachment 31361

 

Oh, sorry. Where do i find the return value from setupEconomy()?

 

Sure that makes sense but where do i find out and change it from false to true?

 

Then.. Like this?
Main Class onEnable:

And then start the server?
EDIT: I just tried this and found out colors doesn't work with this, anyway it said failed so what do i do now?

 

Oh, okay. I changed the essentials.jar file to a disabled file for testing, that's probably why, haha. Thanks for all the help.