Hi,
As mentionned in the above answer, the best way to test the board's outputs is by using MAX, there you can easi~ly switch on and off all outputs of the board.
But that's not the main reason why you're not having output from it. This board has switching outputs, meaning that what you do is closing the connection between the two pins of each output. So, for instance, if you close DO 0.0, you will connect pin 47 and 48. So, you need to connect a signal to pin 47 and when the DO 0.0 if high, you will have that voltage on pin 48. And this answers the question of how much is the high level voltage? It is how much you connect to the high pin of the output untill 60 V that's the maximum isolation it accepts.
About the 5V on pin 49 and 99 that's very strange... you should have 5 V between pin 49, 99 and 50, 100.
Hope this helps,
Paulo