Word cannot complete the save due to a file permission error

Hi all,

        whenever i am downloading a file from local Server(Sharepoint), I am getting a popup like Open-Save-Cancel. When I click on Open, a new instance of word file(.docx) is opened. but when i try to save the document in OPEN mode, I am getting the following error:

        System.Runtime.InteropServices.COMException "Word cannot complete the save due to a file permission error".


        Please Help me in solving this issue.

 Thanks,
K.S. Reddi Prasad.