I had this problem aswell, but with Macafee, and i couldn't take it out of quarantine so i had to uninst macafee ^^ 
I also ran the client throuhg 
http://www.virustotal.com/ and 14/34 antivirus scans showed it as containing a generic artimus trojan...
Also i was talking to a few people on winmx chat, who sujested that it could be being used to steal creditcard details which are then sold over the internet... :S
No idea at all but im currently playing ecsro without an antivirus on my system and im lil bit worried bout it's content. 
  