I believe that Laszlo may actually be on to something.
What are the permissions of the folders and their subfolders? Better yet, if they are read only, or are owned by somebody other than the currently logged in user, or use some variant of Access Control Logic, then the first experiment is to completely rule out permissions. That is, you should make them completely read/write open --including sub directories and see if they are still grayed out.
You might wish to copy the contents of these folders somewhere else, Delete the folders themselves, recreate them and move the contents back. Maybe the operating system considers these to be opened by another program and is refusing to relinquish complete access.
Some ideas
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