10/12: Bagle-AC Worm Sends Fake Message
October 12, 2004

W32/Bagle-AC is a member of the W32/Bagle family of email worms. When run the worm copies itself to the Windows system folder as loader_name.exe and creates other files by appending 'open' to its base name also in the Windows system folder. The worm then displays a fake message box with the title "Error!" and the message:

"Can't find a viewer associated with the file"

More information is at Sophos page.