Apart from highjacking a Nikon thread with Canon-related questions ... this 2s blinking indicates that the flash is in slave mode and ready to fire upon command from master unit. Flip the "slave" switch above the shoe to "off".
My apologies again for the hijack, though I didn't see it as nikon vs canon, its newbies corner after all. Though I don't really understand what you mean, since my flash was mounted on the camera, doesn't have a master mode as well? Nvm I shant ask anymore since its not my thread and not my camera unit =X Thanks anyway!