Empty folders in wp-includes/js/ are causing admin problems

Hello,

I’m not sure if I’m posting in the right forum, but I’ve looked elsewhere for answers and have found nothing so far.

The upgrade to version 2.7 went well. However, I noticed that certain features in the dashboard aren’t working correctly – like the visual editor, the drop down arrows, etc. I did some research and was informed that I should check my wp-includes/js folder and the folders within those folders to make sure everything is there.

The jquery and scriptaculous folders are completely blank, along with a few folders in tinymce. I downloaded a fresh version of 2.7 from wordpress.org, and even those files are empty. I know that important files are missing, and now I don’t know how to find them so I can add them back.

Help?