Hello Lucy4044, Thank you for reporting the error so quickly and with the detailed log; it helped me identify exactly what was happening.
I accidentally referenced the Xparam using id 1, which was actually the id of a basic Param, causing the error you observed.
I made some modifications to the file to resolve this. Could you download the editor again? I just updated it.
I have two important considerations: when exporting the plugin, the file name must be exactly "Kadajah_LvlPoints.js"; it cannot have other characters in the name with (1) at the end or anything similar. After exporting, go to the plugin manager and remove the plugin, then add it back immediately to ensure that the new settings are saved and used. Simply generating the new file may not clear all previous settings.
Also, there is now a parameter at the top of the editor to allow editing already distributed points, and I fixed the appearance of the confirmation screen, which seemed to have an error.
I believe everything is in order now, thank you for the feedback.