Addon Domain: Cannot add and always error

[seobirdfly36]

I have set my domain dns to
NS1.X10HOSTING.COM
NS2.X10HOSTING.COM

but when I add my domain, it always give me such error message:

Error from park wrapper: diygold.com is owned by another user.

what can I do with this error?

 

[descalzo]

You can wait until your other Free Hosting Account is terminated and the system releases the domain name.