An Editor Script which doesn't display the menu Item it is supposed to

This one doesn't seem to work for me:

What error is showing in the console? Do you have Pro version?

The problem is here, missing an 's', i.e. should be Assets, rather not Asset in the line: [@MenuItem("Assets/Build AssetBundles From Directory of Files")]:

The link I referred to in my original above message is actually OK: ttp://

These 2 links present very similar contents, just that one by is the faulty one.