deltaman, you might be confusing voltage and current. "Max forward voltage" refers the the maximum voltage drop that you can expect to see by the diode. The voltage drop is a function of the current going through it, it doesn't care about the applied voltage.
You can figure out the current by taking the input voltage, 240V, subtracting the diode voltage drops (1 for the opto, 4 for the bridge) and dividing by the resistance (2x 30K resistors). Like Kremmen said, it's about 4mA, well under the limit.