Help w/ ABS light and soft pulsating pedal

[atlantis]

I had to replace some batteries and old cables so my 02 F550 sat for about a week and a half while I got it taken care of. Today when I finished it fired right up but the ABS light was on. When i push on the pedal it is really soft and pulsates against my foot. The brakes were great when I parked it and they still work, just feel weird. I have turned it off/on a couple times and problem persists. I did some searching and the fluid res. is up to the line, the seal around the pedal rod that goes thru the firwall has some moist oil around but the oil is dirty like it has been there awhile. When I push on the pedal no fluid come out of the firewall seal but it is moist. What do you guys think? What should I look at next? Thanx