I ran some experiments with the Advanced Sessions plugin today, and the only time I ran into any problems was when I created a project in 4.8 and added the 4.8 version of the plugin, then upgraded that project to 4.9 and did not also use the upgraded version of the plugin. The errors that I saw were different from the ones that you listed, though. I have a couple questions that should help clarify some things.
- Does this only happen in the project that you upgraded from 4.8? If you create a brand new 4.9 project and add the 4.9 Advanced Sessions plugin, do you see the same errors?
- When you upgraded your project to 4.9, did you remove the 4.8 Advanced Sessions plugin and replace it with the 4.9 Advanced Sessions plugin?