Instal SVN version 1.7. Check what is causing the confilcts. You can then rightclick the file and select resolved in Tortoise or if a commit is needed you can commit the change in Tortoise. After that you can do a commit again in the modeler.
All the versions with download link: https://sourceforge.net/projects/tortoisesvn/files/
Version 1.7,15 did the trick!