shadocon89:
I also noticed the little LED on the board itself marked 'L' didn't light up either like it does when I channel the program through to pins 8 and up.
The above makes me believe the LED chase code is working properly since the on-board LED (pin 13) turns on and off; it appears to be more a wiring/LED polarity issue OR the size of the current limiting resistor is too high.
Edit:
Correction - I just caught the sentence "LEDs connected to pins 4 to 7 were not lighting up.."
Do you a VOM to check the pin output w/o connections to the LEDs? The assumption is tht each output has its own current limiting resistor.