This email with the subject "Returned mail: Data format error" was received in one of Scamdex's honeypot email accounts on Tue, 24 Feb 2015 20:15:12 -0800 and has been classified as a Generic Scam.
The sender was "Mail Delivery Subsystem" <firstname.lastname@example.org>, although it may have been spoofed.
Dear user email@example.com, We have received reports that your account was used to send a huge amount of junk email messages during the recent week. Probably, your computer had been infected by a recent virus and now runs a trojaned proxy server. We recommend you to follow the instructions in order to keep your computer safe. Have a nice day, scamalot.com user support team.