Usually DDE errors indicate a corruption problem either with an app or with Windows itself.
- Open an elevated command prompt and run:
hopefully that will fix the issue.
If not, check to see if one of the apps that loads after startup is causing the issue.
You can use MSConfig to temporarily turn off all the extras stuff that load with Windows.
- run MSConfig (just hit start button and type in)
- check "Diagnostic startup" under the General tab
- Click OK and reboot
- and then check to see if you still have same issue next time you shut down
If issue has gone any you need to figure which of your startup apps is causing the issue.
If issue hasn't gone away you will probably need to reinstall Windows.
DDE is one way that can be used to have apps communicate. You could easily break it through overuse and the only fix was rebooting.
It was dated before XP was new and most development apps, if they support it, only do so for legacy purposes.
From Wikipedia: Dynamic Data Exchange was first introduced in 1987 with the release of Windows 2.0 as a method of interprocess communication so that one program could communicate with or control another program, somewhat like Sun's RPC (Remote Procedure Call). It used the "Windows Messaging Layer" functionality within Windows. DDE continues to work even in modern versions of Windows, but has been superseded by newer technologies.
If it's not a corrupted or misconfigured application causing the problem the only fix that I know of is a complete reinstall of Windows. If the error only occurs when you shut down Windows it might be something that you just tolerate until you have to do a reimage. I.E. ignore it till you can't. Keep you backups current!
If you do find a fix let us know!