IgnoreABI is no option for xorg.conf. The option is "-ignoreABI". It is for startx, in kdmrc ,gdmrc or xdm/servers and needed for OLDER fglrx drivers and Xserver 1.4 (Xorg 7.3). Also AIGLX "on" is not a requirement for the new fglrx driver as usually every X server is set to AIGLX on by default.
No announcement yet.
9600(xt) + xorg-server 1.4 + fglrx 8.42