Items required by the macro (slides from another presentation, fonts, graphics, sound files) are not available. Once you create a macro that inserts something into your chart, be sure not to rename or delete that item.

The stage isn't set for the macro to run. If your macro was designed to move from slide 4 to slide 8, it might not work as expected if you invoke it while on slide 5. If your macro will be run during an important slideshow, be sure to test it ahead of time and note the circumstances that must be in place for the macro to do its job.

You've run out of system resources. PowerPoint presentations contain so much graphical content that a machine with marginal resources (memory, speed) may crash or begin to work poorly if your macro opens a presentation or inserts or runs a memory-intensive file. In this situation, it's the hardware, and not the macro, that is at fault. Be sure to close all unnecessary programs before running your slideshow, so that PowerPoint and the necessary files are all that are open during your show.