The UxStyle Core is not compatible with the Windows 10 version 1803 because the project has been abandoned a while ago. However, there is another software that supports all versions of Windows called UxThemePatcher.
Currently, it's capable of patching the following versions and its builds: Windows XP to Windows 10 (RTM, Anniversary Update 1607, Creators Update 1703, Fall Creators Update 1709, April Update 1803) for 32bit and 64bit version.
You can download it from the official website.
Note: Do not run the UxStyle Core because it might break your Windows installation unless you have a backup to recover it from.