Hi, I had the same exact problem and i think i figured it out.
In your Skyrim>Data folder, create a folder called "Scripts", then navigate to the skse>Data>Scripts folder that you download from the site, and copy all the .pex files, then paste them in the Scripts folder you created in your Skyrim directory, this fixed this problem instantly for me. No more SkyUI error notification, and my inventory now opens instantly rather than taking 20 seconds to load.
Hope this helps someone even though im like 7 years late to the party.
p.s. i didnt read every single comment so someone may have already solved this. but here it is anyway. lol
