Hey mate,
I dont know much about HICAS but here is a bit of info regarding the warning light from my R33 handbook manual;
HICAS WARNING LIGHT
This light will normally show for a few seconds when the ignition is first turned to the ON position and then go out. Should this light remain on , or appear while driving, it may indicate that there is a fault in the SUPER HICAS Electronic control system. In this situation, normal suspension will resume.
I am not 100% sure but I think that you may have to replace the HICAS computer, which I think is located under your parcel tray??
Or you could get a HICAS lock.
Hope this is usefull.