Flashing brake light!!! please help!!
 

Ok so i get in my car this morning and my brake light (the one that comes on when you have the parking brakeengaged)is flashing and beping at me. I am freaking out cause this thing wont stop blinking at me. I got all new 4 breaks about 8.000 miles ago. The only thing i could think of is last time i filled up the brake fluid i used DOT 3 cuase i thought a grabed the right stuff but obviously didnt. I dont know if this would have an effect on things. I really need some help cause i am takin a big drive to the auto show tommorow!! thanks