I put the exact url as shown in my admin panel

Right here :D https://vborg.vbsupport.ru/attachmen...5&d=1386285692

I'm talking about the app settings, not your Admin CP. What URL is the app pointing to?

Ok, here, is the same url I have in my admincp

It's been a while since I used Facebook integration, but I'm pretty sure your App Domain can't be empty.

What should I type there? I put my site url www.domain.com and domain.com and it says:
Changes saved. Note that your changes may take several minutes to propagate to all servers.


But when I enable the fb connect from admincp I keep getting the same error :(

Give it a few more minutes then check again. Also, I believe you don't need to included the www, since just putting the domain treats automatically inserts a wildcard option. If worst comes to worst, reset your key, check for spelling errors, etc, etc.

Yup , I delete the www. now it says mysite.com because I dont have subdomains

As I said before I get this error: /public_html/includes/class_facebook.php on line 255

Should I configure that file?

^^ what he said.

Also, have you tried disabling all your plugins and seeing if you still get the same error?

Same error, I guess I wont use it

I also fails, I still can not fix it, I hope you help me, I want people to be able to connect vbullentin 4.2.2 and facebook.