Q: Authentication required when moving, copying files even though I am the only user. How do I disable?

See if this thread helps:

https://discussions.apple.com/message/17741286#17741286

Are you moving files within your home folder, or outside it?

You can't disable it, it's a fundamental part of the operating system.  What you need to do is find out why these messages are appearing so often.  Can you describe the nature of the files you're moving, where you're moving them from and where you're moving them to?  Don't post anything of a revealing nature, however.

Additionally, it's not recommended to use an Admin user for your everyday usage.  OS X is designed from the ground up to work with multiple users, the majority being Standard with a small number of Admins.  I highly recommend you create a Standard user account and use that for your general day-to-day activity, and only log the Admin account when you have to work with System files (eg. when performing updates).