Your host name must resolve to the correct IP address of your server, unless you are using network address translation (NAT).

Please quit Parallels Installer, fix the host name resolution problem,
and then try installing again.
You can skip the hostname check and continue the installation, however,
in such a case, the installer cannot guarantee successful installation.

I’v edited /etc/hosts/ and added

127.0.0.1 webhostplesk 

to it.
It worked… dunno if is the right solution, but it worked. 🙂