Check the file permissions on the %HOMEPATH%\Documents\My Games\FINAL FANTASY XIV - A Realm Reborn\ to see if they are writeable. This is generally only client-side reason for this.

The files you're looking for are:
C:\Users\<ME>\Documents\My Games\FINAL FANTASY XIV - A Realm Reborn\FFXIV_CHR0000000000000000\ (will depend on your system)
GEARSET.DAT
ADDON.DAT
CONTROL0.DAT
CONTROL1.DAT
HOTBAR.DAT
ITEMODR.DAT
ITEMFDR.DAT
UISAVE.DAT
GS.DAT
ACQ.DAT
MACRO.DAT
LOGFLTR.DAT
KEYBIND.DAT