What does it mean if on miumeet that my ip address has been recorded?

[Untoten Mädchen]

Sounds kinda like a prank. Dating sites typically don't "contact local authorities". Even if they do, they wouldn't tell you since that would be giving you time to run.
It's most likely a joke or a prank. Websites record IP addresses anyway which is why if you plan to do illegal stuff, you should use a VPN. Most likely, you're fine as far as the law. However; you could have been hacked...which is not good. In that case, change the passwords for every account you have (email, facebook, myspace, twitter...etc) Also, download this:
http://www.howtogeek.com/101837/malwareb...echnology/
and scan your computer for viruses and other malware.