So, have you connected an LED/scope/analyser/meter/Serial etc. to pins 11 & 12 (no board)? Have you verified outputs exist as expected?
Are your press-buttons/pots working as expected, again, meter and/or output result of press-buttons to other (13?) ports. i.e. intercept the change in the code and call a routine to toggle the pin.
Silly question, but have you double checked your wiring?
A ploy I like to use, is explain the problem to someone who doesn't have any understanding (gf/bf, wife/husband etc. are useful) it helps you to see the wiring/code more accurately without glossing over the bits "you know". Many a time I've got to the point of "and this makes this go..... Oh!" Another bug sorted
Also flowcharting someone else's code can help.
Do you have a simulator? I use this one http://www.arduino.com.au/Simulator-for-Arduino.php
It's still under development, but can save hours. I'm waiting on the latest release.
Both cards work with other sketches without any problem at all,
If they STILL work as expected with other sketches, you have two options - wiring (always a good idea to use different coloured wire
) or code - start breaking it down!
Slightly off topic:
Personally, if I were going to offload the pin count to another board, I'd probably include the ramp too on the driver board and give it i2c communication. Check out the PICs at microchip, they have a massive range of products and a very mature free development system MPLAB. You say you are new to Arduino, but the above is not beyond you