You are right disrupted. This seems a bug, this macro function is lost since 1.5.0 version.
I tested macro work in 1.1.5 and 1.1.6.
NOT work in 1.5.0, 1.5.1, and 1.5.2.
Please report the bug, thanks.
P.S. You could modify the macro to avoid error when cancel button is pressed in prompt for file dialog.
K-Meleon in Spanish