If no fulltext could be created for stored documents please activate the Content Server Debug Log.

Check if following message appears in the Content Server Debug Log:
A part of the path "C:\Temp\DW Content Server\..." could not be found

Check whether the user "Everyone" has full access rights on the temp path of the Content Server and assign this if it is not already done.
Restart  DocuWare services Content Server, Workflow Server and Fulltext Server.