Seems like there's been an error on the web page side.

It has been reported fixed.

https://bitsharestalk.org/index.php?topic=14083.msg183310#msg183310

So, You can try to register your account again.

I've tried registering the BS software on 2 pcs in my home and am getting an error once I try to register my username on the network. I've had this error with both Facebook and Google auth methods. This happens after the webpage opens and I choose my auth method. Please see the attached screenshot. This has also been reported by another user on the Reddit bitshares sub. Please advise why this is happening. Thank you!