Have you tried downloading Combat Arms the 'old-fashioned' way? Goto
https://combatarms.nexon.net, and navigate to the "GameClient and Updates" section you got the loader from(sorry, direct link was censored, and click on the download link just underneath the article about the loader. If that doesn't work either, try downloading the CA setup through download.cne*****m, and just updating it.
@Louzy