A family of Microsoft word processing software products for creating web, email, and print documents.
I had the same issue. I could open Word 2007 with a blank document, but whenever I tried to open an existing document it would give me that error. (There was a problem sending the command to the program)
I did notice that there were two "Recovered" documents in the pane to the left, but anytime I clicked on them I got the error and Word crashed.
I tried a Repair of office and that did not work. Before going to the registry route thought I would do some digging.
After many more attempts to open documents and remove the two "Recovered" documents. It crashed but gave me an option to start up in "Safe Mode". I started Word in safe mode and was able to click on the down arrow on the right side of the first "Recovered" document. This allowed me to delete it. I then opened several documents from the file menu. Then I closed down word and it can open documents again!!
Hope this helps some people avoid messing around with the registry!