The driver's door lock, locking or unlocking itself is caused by the actuator starting to fail. Its very common on J's.
The best place to get parts is one of our sponsors:
http://www.infinitipartsusa.com
OEM parts prices cheaper then your local dealer. I would call them.
As for the ABS light, its likely the ABS module has failed, which is a common age related problem. When you have your hood open(and the engine off), look along the passenger side, you will see a black box, The box lid is is held by clips, gently take it off. In it you will see a black module. pull straight up on it. it will come out. take that module to your local Nissan/Infiniti dealer and purchase a new one and plug it in.
If that doesn't fix your problem, its likely you waited to long between the ABS light coming on and getting it fixed and you've likely burned out your ABS pump.