Hi Jack--
Welcome to the group!
Your request was probably denied because those directories aren't
blocked by your robots.txt file. Check out this help topic for
details:
http://google.com/support/webmasters/bin/answer.py?answer=59819
In particular:
"To remove a directory and its contents, you must ensure that the
pages you want to remove have been blocked using a robots.txt file.
Returning a 404 isn't enough, because it's possible for a directory to
return a 404 status code, but still serve out files underneath it.
Using robots.txt to block a directory ensures that all of its children
are disallowed as well."