You could also try opening up a text program such as notepad and see if the joystick behaves as it should. If your joystick is mapped to the arrow keys, then make sure you type a bunch of garbage text in Notepad and then place the cursor in the middle. Press and hold the joystick and see if the cursor moves repeatedly or just once. Similarly, pressing a pushbutton should register multiple key presses (unless the pushbutton is mapped to Control, Shift or the Shift function in iPac).
To really determine if there is a wiring problem, you could disconnect all but one switch and try again. If it doesn't happen when only one switch is connected, this would point to a wiring problem and you could continue to reconnect switches one at a time until the problem happens again.