I had an issue like that not to long ago. One file somehow got corrupted, and I was not able to even grab it from a working version and added to this project.
After contacting KUKA, the way to fixit was to use a previous image of the controller, and if not present, they would have to send a technician to put a new image on the controller.
I know I'm late to say, but just few information on this.
The problem is that 'RoboticsAPI.data.xml' file has been corrupted probably during shutdown-reboot mostly when the shutdown process wasn't properly carried out. you can easily fix this with simply synchronize again your project from Workbench to the controller.
- If the synchronization doesn't work, you will need to clean everything under 'ApplicationServer\Projects\' and 'ApplicationServer\ProjectRepository\"(might be spelled wrong) on the controller side(using RDC or physically). and then try synchronize again.
