wow never heard of that error before
i looked it up and as far as i can tell something goes wrong with the path when it tries to create a file
the only instance i found was that it can happen if a folder or something else in the path has a space in it, but that doesn't seem to be the problem looking at what you posted. I wish I could help but it seems like it has something to do with specific files/folders on your computer. You could try to navigate to C:\Users\SeanMcDonnell\AppData\Local\Temp\ixp001.tmp\peppered.exe when the error shows and see if a folder is misnamed.
otherwise please feel free to contact the itch.io helpdesk and get a refund!