In this case, the images were nested in directories inside of directories inside of directories inside of directories about 6-7 levels so the path was just too much for Instruction Writer to handle. So we lessened the number of directories and then it worked fine.
The giveaway was that the customer could get some illustrations to work while others would not.
It can also happen if the file name is too long. Try shortening the file name and see how that works.
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