First, you should export a project package so whatever happens you dont lose your changes. You can do that under File > export project package. Then when you go to your project directory in file explorer there will be a .mpr file in the packages folder. I would copy this file to your desktop.
I don't have much experience with this issue, but the other day when I was committing, my modeler crashed which prevented me from committing once it restarted. I was able to commit my project through svn, and that fixed the issue for me.
If that doesn't work, you can try opening the copy of your project package and committing that project. The error seems like its having trouble locating your project files.
You can try this: