[Hjälp!] PHP PDO prepared query's

$dbh=new db();
				$query="INSERT INTO ".$dbh->prefix."users (username, password, mail, firstname, lastname, ip, remote_addr, regdate, usertype)VALUES( :username , :pw , :fname , :lname , :ip , :remote_addr , :regdate , :type )";
				$input=array(
				"username"=>$username,
				"pw"=>$pw,
				"fname"=>$fname,
				"lname"=>$lname,
				"ip"=>$ip,
				"remote_addr"=>$remote_addr,
				"regdate"=>$date,
				"type"=>0);
				if($dbh->execute($query,$input)){
				echo 'admin added';
				}
				else{
					echo "some thing went wrong...";
				}

function execute($sql,$vars=null){
		$run=$this->dbh->prepare($sql);
		$go=$run->execute($vars);
		if($go) return true;
		else return false;
	}

Warning: PDOStatement::execute(): SQLSTATE[21S01]: Insert value list does not match column list: 1136 Column count doesn't match value count at row 1 in C:\public_html\s\cms\lib\db.class.php on line 53 some thing went wrong...