It seems that the publishers have lowered the minimum requirements since the Beta. See those official data:http://na.finalfantasyxiv.com/#/about/game_info. From users' experiences, however, it still seems a very demanding game which should only be tried on better specs than those very minimal ones. As Irfan said, an exact error message about the incompatibility issue would be helpful.
EDIT: After a quick look to the dedicated gamers' forums for FFXIV, the ffxivboot.exe file is known for several issues (crashes, "stopped working and must be closed", incompatibility). No common cause found until now.
"192 GB ought to be enough for anybody." (from the miniseries "Next Generation's Jokes")