如何使用Heroku上的Zerigo DNS将根级别域重定向到www子域？

我无法将根域重定向到www子域名（（例如blahblahblah.com到www.blahblahblah.com）。我有一个托管在Heroku上的网络应用程序，我通过Zerigo DNS修改了DNS设置

I'm having trouble redirecting my root domain to a www subdomain ((e.g. blahblahblah.com to www.blahblahblah.com). I've a web app hosted on Heroku for which I've modified DNS settings through Zerigo DNS.

这些是我当前的设置：

但是，这是我输入时出现的错误，比如说blahblahblah.com：

However, this is the error I am getting when I type in, say, blahblahblah.com:

是否有问题或者有什么其他事情需要做，以便重定向工作？

Is there a problem with how things are currently set up, or is there anything else that I need to do in order for the redirect to work?