It could be possible that the registration time had ran out by that time.
I suggest waiting until it opens again (random times). Keep in mind that it's only open approximately 2 hours a time.
If it still won't work, try contacting one of the staff members (http://www.feral-heart.com/index.php?option=com_content&view=article&id=28&Itemid=52) through PM.
Like Ressy said above, you could have extended your amount of time to registrar. You best option is to try again when it does open up so just keep checking back on the site from time to time and re-registrar again.
Now its impossible to know when the registration will open since it is programed to open at random times But asking staff to open a account that isn't even active isn't something they do really if its not even there. It wouldn't hurt to ask staff though to see there input.