Could not use the black point tool because of a program error

I'm using a curves adjustment layer to colour grade an image on top of a background. I can use the eye dropper tool to select the black/grey and white points in the background but when i go to apply them to the image it gives me the error 'Could not use the black point tool because of a program error'. I have tried clearing perfs, didn't work. I'm using RGB, 8 bit colour channel.