x10 recently changed the functioning of PHP in order to decrease potential for abuse. You need to upgrade your version of PHP to the Intermediate level. A new option has been added to your cPanel which allows you to upgrade your version of PHP to a less restricted version. I would suggest you choose the Intermediate option, as it is the easiest to be approved for (you can switch to this option without supplying a reason) and because it supports the eval feature. If, after upgrading to the Intermediate version of PHP, you are still having problems, you may then ask for the Advanced option, however you will have to supply a valid reason (the error your script returns.) Keep in mind that this change happened a few days ago, and many members are requesting less restricted versions of PHP, so it could take up to 24 hours. I requested the Intermediate version, and it didn't take long at all (within an hour I think).
You can find more information on this (from people who actually know what they are talking about) here:
http://forums.x10hosting.com/news-announcements/30267-important-php-changes-read-all-servers.html
Hope this helps!