Thanks for your fast answer.
I promise I do my maximum, but I cant make it work.
When I redirect the main donain to the IPs you gave me I arrive to http://www.professorparticular.org/cgi-sys/defaultwebpage.cgi so the "If you feel you have reached this page in error, please contact the web site owner:"
My file are in "public_html/www", so it shouldn't happen.
And when I try to add a .tk, after configuring correctly in dot.tk I get this error in the cpanel:
Using nameservers with the following IPs: 188.8.131.52,184.108.40.206,220.127.116.11,18.104.22.168 Sorry, the domain is already pointed to an IP address that does not appear to use DNS servers associated with this server. Please transfer the domain to this servers nameservers or have your administrator add one of its nameservers to /etc/ips.remotedns and make the proper A entries on that remote nameserver
(I moved back the main domain)