HELP ! Potential hack attempt ?

Hello there guys.

I write in potential emergency, because my blog has potentially been the target of a hack attempt, and with very little chance, who knows, it may have had success, even though I doubt it…

I need your opinion, in other words.

I just received this email, 18 months after I created my blog :

title :
New WordPress Blog

Body :

Your new WordPress blog has been successfully set up at:

http://www.myblog.net [I’m sorry the URL needs to stay private]

You can log in to the administrator account with the following information:

Username: admin
Password: User already exists. Password inherited.

We hope you enjoy your new weblog. Thanks!

–The WordPress Team
http://ww.wp.xz.cn/

—–

Do you guys think this is a hack attempt ?
And if so, do you think it has succeeded ? Given I have a long and complicated password for the admin account, I doubt it can be brute-forced, but well, I use an old wordpress version, 2.1.3.

Thank you VERY much for your opinion and advice 🙂

I would hate to discover some day that an iframe has appeared on my blog or that the ad banners have seen their code replaced with someone else’s code…