Security Credentials Error

I was going through the install instructions included with the downloaded zip file of Arcane and everything was working great until I hit the part where I can actually start making changes to my site. Any time I try to make changes, I receive an “invalid security credentials” error. I can’t figure out what username/password I’m supposed to use in order to make this theme functional. I’ve tried everything from my WP password to the one I use with site, and admin/admin, with no effect.