Ok I will try it now.

And I have a same problem with http://www.gaywall.nl/ I try to enable DEBUG and DEV mode, deactivate Start Page Pro and Watchdog but still I can't register.

On GW.eu it's ok thank you Aliia!! :) I reinstall watchdog and registration is now OK! :) now I try to disable DEV and DEBUG mode and try tu register again. 

Give me 5 mins to check your second site.

Yesss :) Thank you

Let's remove snowing effect

Removed. Still not working. :(

I can try to restore DB from my hosting provider.

And also deactivate plugin related to following keyword "photoverifi"

You mean User photo verification ? Ok I will disable it.

Still now working.

On another note, User photo verification was causing errors on your site when trying to login using FB connect.  So you might want to contact plugin developer if you are planing to use this plugin in future.

But on GW.eu I have this plugin too wothout any errors. And when I disable FB connect it will be ok?

Regarding registration issues on your second site.
Will you be able to to PM me your FTP and admin panel access details?

>>But on GW.eu I have this plugin too wothout any errors. And when I disable FB connect it will by ok?

I didn't have time to take a screen shot of the error. But it was something related to databases. So the issues might have been in just incorrect installation and not in the plugin itself.

You can always activate this plugin, login using FB connect and get the error.

Waiting for your reply regarding access details.

Ok:) thanks.

I PM you access details.

Thank you. Will keep you posted.

Resolved.
Registration on second site didn't work because of following plugin:  Users Quick Search + Site Search