You should probably save your project online and raise a ticket to tell customer support the name of it.
If you open a file that is giving you problems, save it with a DIFFERENT file name. That way if the file contains problems or is corrupt, you will not be overwriting your original file.
One possibility is that the last image you added was too big or problematic in some other way. Possibly multiple images or the project layout is contributing the the problem.Try deleting just that most recent image and saving the project with a new name. See if that allows you to open and publish the remaining portion of your project. If customer support takes a look at your project, they may be able to suggest ways you can improve your project to avoid future problems and finish it successfully.
Or you can save it as a .scribe file and attach it here if you want other users to look at it.
-Mike (videoscribe user)