Error message when downloading Norton AntiVirus 2010 program

I keep getting an error message when trying to download the 30-day trial version of Norton AntiVirus 2010. It says "Security Warning" - Applicaiton cannot be executed. The file control.exe is infected. Do you want to active your antivirus software now?"  Sometimes it has different file names on the messages too. Is this a virus that has already infected my computer?

 

Teresa