Access from MAC to remote disk

[Pauliine]

Hello,
I have a MacBook Pro. I've connected an external hard drive through USB to our router. I'm trying to use that as my backup drive. However, whenever I copy a file, it says I do not have sufficient privileges. I can open existing files on the hard drive with no problem. I can copy to the hard drive if it's connected to the USB on my laptop. But, through the router, I'm having issues. Any suggestions??
Thanks!

 

[Pauliine]

I just realized that I should have probably posted this elsewhere. I don't know how to move it though, so just copied it to the storage section.