Hi,
yes, Becca is absolutely right - would be nice to know what kind of pad this is!
Adding to that: most devices on the parallel port use the data pins (2-9), the other pins often serve other functions (see Parallel port - Wikipedia ), so it is completely fine that some of them have other values or that you cannot access them.
Still your pins 2-9 seem not to respond to the button presses. Maybe this is indeed related to the problem I once experienced: Reading from parallel port - #2 by ulrikeh
There I used the pyserial parallel module instead of the psychopy module because I could then set the port to “reading mode”. Have you tried the code of that thread?