Here are some addresses in which you can write Arnold at:
Oak Productions
321 Hampton Dr. #20
Venice, CA 90201
Schatzi On Main
3110 Main St.
Santa Monica, CA 90405
c/o PMK
955 S. Carillo Dr.
Suite 200
Los Angeles, CA 90048
c/o ICM
8899 Beverly Blvd.
Los Angeles, CA 90048
c/o ICM
8942 Wilshire Blvd.
Beverly Hills, CA 90211