As corey said, your account is on the server which is moved at the moment. so have patience. http://x10hosting.com/forums/news-announcements/115601-updates-upgrades-etc.html#post659952
The mysql host should be localhost
$mysql_host="localhost";
the database name should be like cpanelusername_databasename
the database username should be like cpanelusername_databaseusername
First you have to set the nameservers to ns1.x10hosting.com, ns2.x10hosting.com
the nameserver propagation may take upto 48 hours.
Then you can park the domain in your cpanel.
Can you provide us the cpanel username to check what happened to your account.
The servers are under move at the moment. So that may be causing the issue that you are not able to access.
Generally that is the case happens. But the time depending on number of accounts in the current case of server move. Once everything is moved, the sites will be up normally. The rough estimation is given in the thread by corey...