Trying to Create a Dimension

It worked fine for me. You did not include any logs so I can only guess it is this:

In some cases, Gradle caches that make sure the build process does not take too long can get corrupted. In such a case, go to:

<your user home folder>/.mcreator/gradle

In this folder, there is a folder called caches. Delete this folder and open MCreator again. Next build will take a bit longer as caches need to be rebuilt. If you can not delete all files in this folder (which is necessary), reboot the computer first to remove any potential file locks.

If this is not enough to make things work, delete the entire gradle folder, not just caches, and try again.

If even this fails, try to delete the entire <your user home folder>/.mcreator/gradle folder, create a new workspace with the same generator version as the version of the workspace failing, after the setup of this new workspace is done, open your current workspace, and click Build & run -> Build workspace, then Build & run -> Reload gradle project and then Build & run -> Regenerate code and build.