What can be the problem that nobody can login on

http://viralz.eu

see: http://c2n.me/3za6p4Q.jpg

can't check the terms and site think is want to send spam...

Didier

Are you actually running viralz.eu ?

I have performed a web search on the screenshot error you supplied and Google reCatpcha doesn't produce this error, so it must be coming from somewhere else.

Did you add any code (js, php, html, etc) to your login page?

I would suggest to check Antispam module rules and settings