That's an old chestnut issue, resolving to there being too many files in
the directory to be manageable, as previously discussed in the List.
A directory is a very primitive data structure and thus very inefficient.
Any UNIX system which has an enormous number of files in one directory
bogs down very thoroughly.  Administrators of mail and news servers know
all to well of this.  For the sake of your system performance in general
you need to keep no more than a few thousand files in a directory, so
endeavor to make your directory structure a steeper pyramid.
In the mean time, you will have to dramatically boost your timeout value
to accomplish ADSM operations on that directory.
      Richard Sims, Boston University OIT