So what I did to solve this:
Ran the command that failed from the command prompt. This gave a more detailed error saying that it ran PostBuild-1.bat and that there was an invalid amount of parameters.
Located PostBuild-1.bat to \Engine\Intermediate\Build\Win64\DatasmithSDK\Development
Opened script in text editor, found the error to be that spaces in file paths weren’t accounted for. To fix this, add quotation marks around every file path on lines starting with “xcopy” and save the script.