Disconnect the PICAXE and activate the phototransistor and measure the voltage at the emitter, as seen by the PIC, does it go to zero when off and +5.1V when on?
Have you set the PICAXE to be an Input on that pin?
I thought the command
if pinc.6 = 1
would cause the pin to be set as an input. Not so?
Yes, the voltage at the emitter is zero when off and 5.1 when on.