This happens when a file has not not been completely downloaded. Please use the link provided in your Photomorphis receipt to access your User Dashboard. Download the files and keep an eye on the progress bar to make sure they are complete before unzipping them. You’ll have more success if you download each file, one at a time, rather than clicking on all of them at once.
The texture folders contain jpeg image files so they are fairly large and it can take a while especially if you have a slower connection. Tutorials and BlendKits are even larger (up to 400 MB) so please give them adequate time and pay attention to the progress bar. Unzip the file only after you're sure it is complete.