I get this image after reinstalling the game and all of my original mods. Never seen it before. I can click the checkmark and the game seems fine. Has anyone seen this before? Uploaded as "mastercontroller". Had to upload as .rar since it wouldn't let me upload the actual screenshot.

That error is coming from AwesomeMod. Either you don't have the base MC file installed or it's corrupt and should be re-downloaded. In the event none of that works perhaps Awesome is broken.

I could be totally up the wrong tree barking (or whatever noises a platypus is supposed to make), but I think Awesome will throw that error if the player mistakenly has multiple instances of MC (or MC Cheats) installed as can happen by accident when mods are included in the merging of content. Or when the scriptCache is not cleared in between cleaning up or adding to/deleting from Mods\Packages and Overrides in any way.

But yes, I imagine not having the MC base mod in the first place or it not loading properly might also trigger something like that.

Yeah, it turns out I didn't install MC first! I know I downloaded it but somehow that didn't get put in the Mods folder. It's all working now!