Yeah i faced the exact same issue, wanted to make alternative whatsapp thing just using apps and now the extra email thing is causing hassle, however that said you can register users manually and that will create passwords, like open registration feature, which is by default is enabled and head to your RC webpage and register. open it in incognito
I often find that the ACT of posting something makes me think about it and fix the issue. The issue was that I was zipping the folder that contained the files rather than making a "flat zip" file. It is working now.
Ah, so you had to zip the contents is all, rather than zip the folder?
Okay, so the fibers issue is related to it not liking the NVM installation of Node.
So on CentOS 7, the secret is to install the epe-release, then install nodejs. This installs Node v0.10.36, which is not what anyone wants. But once that is installed, you can go back to using NVM and a modern Node release and fibers is able to install!