Although I usually am against the calling of double fouls, this sounds like a situation is which it may be justified. This call is different from the charge/block where one official calls the charge and the other calls the block (in which case, I believe there never should be a double foul call). In the case of the charge/block, I believe you cannot have two interpretations of the same act prevail.
In this case, however, you have two separate acts. The defender committed a block at the same time the offensive player pushed off with his arm. The two fouls are not mutually exclusive. It sound to me like the right call was made.
AAARRRGH! Now I'm agreeing with Rut! What's next - a candygram to Yaws?