cant load worlds or create new ones, game says errors in currently selected datapacks

I just updated my mcreator so i could use geckolib, and now after adding and activating the plugin, none of my worlds will load and i cant make new ones. I looked through the crash log, which i dont understand any of, and saw something about the structures in my mod so i got rid of all of them but still no luck. i read some things about datapacks but im lost on what exactly to do and im getting frustrated. anyone able to help?