Can't create admin!?

[DrByte]

I didn't install anything that wasn't from your download site.

All the addons/contributions in the downloads area are use-at-your-own-risk. While the majority of them are solid, some are in-development, and some are poorly-written or ill-conceived. It is up to you to test the usefulness of anything you decide to add to your site ... ideally testing on a "test" copy of your site before you put it on your "live" site.

Sometimes I was supposed to copy a php file to a folder that didn't exist. It asked me to go to YOUR_TEMPLATE with languages>English but my template wasn't in there so I simply created a new folder with the name of my template and copied the file in there. Does that sound correct?

That is often a logical choice.

I am using a CUSTOM template. I was thinking that creating a new folder could have been wrong and that that might have caused the bug in the database.

I'm not aware of any bug in the database.
Creating template folders should have no impact on the ability to create admin users or change admin passwords.