Your network access was interrupted. To continue close the database and then open it again. Windows 7

I've got a new problem that cropped up some time ago and only today did I find some critical information about this problem. Every once in a great while, with no consistency, a user will come back to their workstation and find the following error message on their screen:

"Your network access was interrupted. To continue close the database and then open it again."

We have our 2002/2003 format MS Access database backend stored on a shared drive on our SBS 2008 server. All the workstations are connected to the domain and they each have a local copy of the 2002/2003 format MS Access database frontend on their own hard drive. The server is a high performance dell with (4) 15K RPM hard drives in RAID 5, 12GB of memory, (2) Xeon processors, and gigabit wires to an unmanaged Netgear switch. All the workstations are gigabit as well. The server does file sharing, printer sharing, DHCP, DNS and MS Exchange on our small network. We have 8 workstations in use on a daily basis and two workstations that get used occasionally.

All the workstations are running Office 2007 or Office 2010. This problem affects both 2007 and 2010. All workstations have MS Updates turned off but we do bring them up to date every few weeks.

All of our Windows 7 workstations are having this problem andonly our Windows 7 boxes are having this problem . These Windows 7 workstations are all 32 bit Dell Optiplex 760 or 780 minitower desktops. The machine I'm currently investigating has a built-in Intel 82567LM-3 Gigabit network adapter with driver version 11.6.92.0 from 4/12/2010.

We are using MS Server Backup on the server. I'm fairly sure that this problem is not related to the backup because the problem does not correspond at all with our designated backup times.

I'm quite sure there is no interruption in network access. All of our XP workstations do not have this problem, including both those that are heavily used and those that are used lightly. I've checked for errors in the event log on the server and the Windows 7 workstations and there are no related errors logged on either one. There are no distantly related errors. Nothing is logged around the time of the so-called "disconnect". I'm quite positive the network is not dropping connection at all, and if it is, it has to be the sort of hiccup that is so brief that there are no popups, warnings, errors, etc., other than this MS Access problem.

Our network is a controlled environment. We have content filtering using OpenDNS and we have Norton Antivirus 2011 installed on every workstation. We haven't had viruses on any of our workstations in a couple years, maybe more. We don't have any other applications giving any error messages remotely similar to this.

I do not believe this is a problem with our network as it is fast and rock solid. Our server is very clean and never needs rebooting unless we are installing some kind of updates or software that requires it. I do see a lot of other posts online about this problem but so far there don't appear to be any solutions, only the standard rhetoric of "check your network" which is clearly not doing anything to escalate and solve this issue.

I did have to make some changes in the registry on our server right after we rolled out the new server. The changes I'm talking about are specifically "Turning off the sharing violation notification delay". You'll see this documented on Microsoft's website at http://support.microsoft.com/kb/889588 . We made these changes because there was a very long delay when more than one user was using the database. This was also true of our 2003 Server and we had made those same changes on there as well.

How would you recommend troubleshooting this issue? I can probably do wireshark if necessary although the problem is fairly infrequent, maybe once or twice per day. It will require running any analysis tool for many hours in hopes that the problem occurs.