just rename the file you downloaded to Carepackagerain.iwd not Carepackagerain.rar then make a folder called mods in your MW2 installation directory and when in-game go to the console and type fs_game mods/Carepackagerain;vid_restart and hit enter then type party_hostmigration 0; party_connecttimeout 1 then hit enter again and done... select Play, Find Game and go FFA or whatever... then just wait for players join and ur host and viola!