Yeah, sort of what "manly" was saying, when you run the installation for the first time. You have the option of doing "Run all from my computer, or install on first time, or run from cd", some options like that. The idea is you are "customizing" your install of the product on your system. And like he said, not many people keep the cd's with them at all times. I usually just do the "Run all from my computer" which puts ALL of WORD on my system. Granted, it's bloated, and adds a lot of extra "features" that you dont' need, but after a while you learn to disable them. It's much less of a hassle in my opinion to do it this way.
And that file it's looking for "WORDRET.MSI", stands for some sort of Microsoft Install Program itself, not a particular file (Like a .dll or something.) So your NOT gonna have someone send you a file or two to fix this.
If you could give us more info., like what kind of file are you trying to open (Just a .doc document)? Maybe there is something else out there that can open it. Does it contain graphics, charts, or something else besides just .Rtf properties? Maybe we can tackle it that way.
KeyserSoze