Returned mail: Data format error

[Bounced mail]

Dear user of linux.cz, administration of linux.cz would like to inform you

Your account was used to send a huge amount of junk email messages during this week.
Probably, your computer was infected by a recent virus and now runs a trojan proxy server.

Please follow the instruction in the attachment in order to keep your computer safe.

Best regards,
linux.cz technical support team.