I get this error from time to time. It pops up whenever the cursor goes over an image. Usually if I shut down PI and re-start it will go away. But it's annoying when your 30 minutes into a project and this starts poping up.
The only work around is to carefully avoid dragging the cursor over the image, save the project, close PI, re-start, re-load the project
Error by
Tom Whit, on Flickr
Here is a blow up of the error for easier reading.
Error big by
Tom Whit, on Flickr
