By any chance you'll be in Spain? that is very similar to what we are experiencing many:
http://community.x10hosting.com/threads/i-cant-access-my-site-from-my-workplace.190633/...
is the same problem described here: http://community.x10hosting.com/threads/i-cant-access-my-site-from-my-workplace.190633/
I I can not see your page: http://cursosfpoweb.es
you can see that your website is online really if through a proxy, for example...
Same happens to me for over 24 hours, I've proven to change my IP and nothing, I can only access through a proxy IP from another country. I think there is a kind of banishment to the IP of my country: Spain.