Ping the server that you're hosted on (eg., if you're on Stoli, ping stoli.x10hosting.com), then set the DNS 'A' record to that IP address. Then you have to add the domain via cPanel as parked or addon.
Edit: To ping, go to start, run.
Type cmd
type: "ping yourserver.x10hosting.com" (without the quotes) then hit enter.
Then use the first IP address that appears.
Another edit: VISTA USER
Click start
Type cmd in the start search box.
Right click cmd in the results list
CLick run as administrator.
Okay the UAC message.
Then type "ping yourserver.x10hosting.com" then press enter