Well, I can't help with the trackball, but as to the LED.
First, LED stands for Light emitting Diode, which you probably already knew. But... A diode will only allow current through it in one direction. This means if you wire it up backward, it won't light at all (but as far as I know, you won't blow it out either, it just won't work).
For most cabinet type LEDs, a quick and easy check is to take a little button cell 3 v battery (like a CR2032) and connect it to the LED, if you connect it right, the LED will light.
Those little batteries don't put out enough current to blow the LED so you don't normally even need to bother with resistors when testing like this.
The PACLED64 is a constant current supply, which is great. It means that you dont' need to bother with resistors when connecting the LEDS.
Just make sure that that the NEGATIVE pin on the LED is connected to whicheven pin is applicable on the PACLED and that the positive LED pin is connected to one of the + pins on the pacled.
See here
http://www.ultimarc.com/pacled64.htmlAnd finally, you can daisy chain the POSITIVE led pins together so you don't have to run a seperate wire from each to the PACLED.
You CANNOT daisychain the NEGATIVE pins though.