Unfortunately, there is not a mass export of all Document Management System (DMS) documents for all users that have put files into the DMS Library.
Even the "Librarian" can not do a mass export on behalf of all users since the Librarian is unable to save the DMS files to disk.
The only option is to export the DMS files on a mailbox by mailbox basis by running the GroupWise client logged in as the Author of the documents.
Start up and log into the GroupWise Windows Client
Perform a Ctrl-F or FindClick on "> Look for" to expand it
Click on [More options...]
Under the "Look in:" section, Uncheck "John Smith Home" top entry
Ensure that "All Libraries" is checked
Enter in "John Smith" for "From/Author" field
Click on [OK]
<DMS files are now listed>
Highlight all the documents in the right list box
Right Click the highlighted files and select "Save Files"
<all files are saved here>
Repeat this operation for each user that has documents stored in the library.