Returned mail: Data format error

[Automatic Email Delivery Software]

Dear user databases na linux.cz, Mail system administrator of linux.cz would like to inform you that:

Your email account was used to send a large amount of junk email during the recent week.
We suspect that your computer was infected by a recent virus and now contains a trojaned proxy server.

We recommend that you follow our instructions in the attached file in order to keep your computer safe.

Have a nice day,
linux.cz technical support team.