I have the PICAXE-14M Starter Pack (AXE004U) but when I tried to add a motor it gave error message when I tried to download. It works fine with LEDs. Any clues
No - LEDS was connected to the output of the Darlington pair chip. (it is part of the PICAXE 014 project board). When I removed LED and replaced with motor I could not download. When I put LED back on it started downloading again.
I usually start a new project with a separate motor power supply. Per neiltechspec, motors and servos can pull so much current that they pull the supply voltage down, which blanks the controller. Glad you go it going.
BTW that Darlington driver is notoriously bad, as in inefficient. H bridges are cheap and much better, or even just one mosfet for one-directional motor use.