Unable to save previously saved 2007 Word document on network drive only

I am running Word 2007 under XP Pro networked to Windows Server 2003 Standard. When I try to save a previously saved document on the network (not doing a "save as"--this works fine as the network sees it as a "new" document) I receive the following error: "Windows cannot complete the save due to a file permission error. (filename)"  when I try to save it again. The error code is 200635. Further complicating the issue, if you click "Ok" on the error message and retry the save the error recurs anywhere from 2-6 times but then properly saves the document exactly as I was trying to do each time the error message previously appeared. I have no problem saving to my local drive.  I am able to save (and re-save) to the network drives if I log on from anyone else's machine using my same user profile. Any other user on my network has no problem saving (and re-saving) to the network drives if they log onto my machine. No one else has encountered this error on their own machine. We have checked and re-checked the permissions. All the other Office 2007 applications work perfectly. In addition to Office 2007, we run Workshare Professional and I am also running Dragon Naturally Speaking 9. We run Symantec Endpoint Protection on each workstation. According to Microsoft's KB, this issue may be related to certain anti-virus products. Of course, they have no solution. We've tried uninstalling and re-installing not only Office but also the Symantec Endpoint Protection. Even without the Symantec product installed, the error still occurs. Any thoughts?Start Free Trial