I cannot open word files listed by clicking on them. Windows reports "Windows cannot access the specified device, path or file. You may not have appropriate permissions to access the item".
This seems like a rather obvious error, yet I cannot find any information to resolve it (after some search).
Also, you may be able to make it work by using the Open With menu (right-click the file, Open With, then Choose Default Program) to assign Word to the file type. Opus should respect that.
Sounds like something odd has happened to the file type though, which my FileTypeDiag tool may help to reveal.
In Opus, could you paste this into the location field:
C:\PROGRA~1\MICROS~2\Office12
Then, assuming the folder exists okay, confirm that there is a file in there called Oice.exe
If Oice.exe exists, could you try dragging a .doc file on to it to make it launch the file. Does that work okay?
That seems to be the file which Opus should be running on your system when a .doc file is launched. I think Oice.exe is installed as part of the Office compatibility pack (that restores compatibility with very old versions of the .doc format).
If you haven't already, it might be worth checking that you've got all the latest Windows and Office updates via the Microsoft Update site. (The one that updates Windows and Office. There should be an option to use that extended update service within the Windows Update site.) I say that as I saw a couple of articles which mentioned problems with earlier versions of Oice.exe and filetype settings, but they weren't very specific so I don't know if they really apply.
I tried dragging a .doc file onto Oice.exe and got the same error message.
Opus has proved too difficult for me to work with, and as I have a file manager which is reasonably good (PowerDesk Pro 7) and just discovered a current version of my original file manager, XTree (ZTree Win) I will work with those in the future.
In that case the regsitry, or the Office compatibility pack install, seem to have gone wrong as Oice.exe is what the registry is saying should be used to open .doc files. (It could be that the file permissions are wrong on Oice.exe and your account cannot run the program, too.)
Perhaps Explorer detects this problem and falls back on another launch method while Opus reports the error. Just speculation as to why they are different, though.
Of course, if Opus is the only thing the problem affects and you've decided not to use it then it's a moot issue, but if you run problems launching Office files again in the future then I'd recommend doing a Repair of Office via its installer. That should return things to normal.