The problem is clear. There is a space between Research and Projects in your directory structure. You can rename this folder, then it should work.
The issue with spaces occurs anywhere in the file name path - not just the image file names.
The good news is that the fix is easy, and secondly, that you can open the existing .xml file for the project and go straight to building RTIs on the last screen, since you have already detected spheres and highlights. RTIBuilder will ask if you want to reset the path (since the stored path will be different) say yes - and away you go.
Instructions for opening an existing project can also be found in the user guide.