Can't launch MoP client (5.4.8)

Hey guys
I'm already playing on icecrown since some months and i wanted to try MoP server. I downloaded 5.4.8 client from this website but i can't launch it. Sometimes the error message is "Download failed. Check your network" ; sometimes it's "Data/frFR/wow-update-frFR-18273.MPQ . Can't load the archive feed required"

It's not my network because i can still play on icecrown. I tried to desactivate read only on my MoP folder but each time i go back in properties the read only mode is still here (yeah i press ok or apply). I don't have any antivirus, only Windows firewall.
I tried to change the realmlist from "logon.warmane.ru" to "logon.warmane.com" but nothing work...
Any help ?