Hi @kuri, I hope you were able to figure out the issue on your project.
This is most likely an issue with Python 3.13 loading an older version of tk-core which is not compatible with Python 3.13 (Python 3.13 is unable to load the six module).
We recently updated the “IMPORTANT - Toolkit Configuration Version Requirement” section of the FlowPT Desktop v3.0.0 Release Notes. You might find useful information there about your issue.