The error seems to occur regardless of where the file is located. The 'browse' button allows me to select the .swc file I want to analyse, however the 'ok' button becomes unclickable when I've done so and the error message remains.
Copying and pasting the path from file explorer has the same effect.
Also, if 'load traces without images' is unchecked, the error message also says the image file is invalid, regardless of whether an image file has been selected or not.
Yes, those are the versions I am running.