looks like the same old problem of people upgrading to the new PHP version.
in icehorse site you might have old version of PHP which has register globas on by default, and your code is simply using the input names as vars in the php side.
but in new version (from php v4.2.0) the register globals are turned off... so you have to access the input names by $POST['input_name'] or $GET['input_name']
hope this help,
Daarius...