Adobe Reader is the "reader" part of software from Adobe Systems meant to handle portable document format files. The PDF file format creates a fixed image of a document and presents it much like the page of a book. The unique layout of these documents requires a special reader. The DDE error is a glitch that may occur due to a bug in the current version of the reader or a conflict with a background program.
Dynamic data exchange is a tool associated with the Microsoft Office programs according to Microsoft. DDE works to help manage communications and data sharing over a network. If you are getting an error for Adobe Reader regarding the DDE server, your system has problems exchanging data with another system for some reason. It may be difficult to figure out exactly why, because there are a number of variables. You can try some basic troubleshooting techniques to see if that resolves the error.
Companies like Adobe Systems are always working to improve their current version of software programs. This is partially because other programs are also constantly changing. In other words, an application that works in concert with the reader to share to data for instances may not be compatible with your current version of Adobe. There may also be a known bug in the version you are using that accounts for the error. To fix the problem, you may need to upgrade to the current version. If you go to the Adobe website, you can download the upgraded reader program.
This or any error could be the result of an installation misconfiguration. When you installed the reader, there may have been a file that did not download or install properly. To fix this issue, you uninstall the reader and download it again. To do this, go to the Control Panel and open the "Programs" section. Find the reader on the list of software that appears in the dialog box. When you right-click on the application name, you will have the option to uninstall. Once the reader is off the computer, you can visit the Adobe website and download the reader again.
It is possible another program running on your computer may also cause this error. This would be a third-party application that you have active in the background at the same time as you try to open the document. Try shutting down any running applications before opening the reader. Looking at multiple documents at once may also cause the error. This would still be a glitch, but reading one PDF at a time might be a temporary way to fix the problem.