Map problem

[seymour110]

i just bought and downloaded civ 5 on steam today, wanting to play the earth map i selected the english and began to play....only to realise that i was not playing the earth map! so basically even if i select any map civ5 always seem to select something different...usually a big landmass even if i select the archipelego map! has anyone else had this problem and how do i go about fixing it?