What is it?
tasker.exe is a file associated with the mass mailer W32.Mydoom.R worm

What does it do?
W32.Mydoom.R@mm is a mass-mailing worm that uses its own SMTP engine to send itself to the email addresses that it finds on an infected computer. The email contains a spoofed From address. The subject and message body vary, and the attachment has a .bat, .cmd, .exe, .pif, .scr, or .zip extension.

More info and Removal instructions
@symantec