The cause of this is error is that Microsoft Word is not completely installed on your computer.

In order to rectify this problem, follow these simple steps:

1. Click on the "Start" menu in Windows
2. Click on "Run..."
3. Type exactly the following in the textbox: ”winword /regserver"
4. Press "OK"
5. Wait for few seconds until Word complete runnings
6. Restart your computer and try A2E/A2D conversion again.

With Able2Doc or Able2Extract, you can also attemp the PDF-to-Word RTF conversion. This will work even if your computer has no Word installed.