I just tried the instructions for opening files in Lion's Den that want to open as ZIP files. (I posted here last week and that process did not work this time, of course!). I did find another work-around however, and will try to describe that process.
In Lion's Den, click the file and select to SAVE it. Save to Desktop or My Documents.
Go to the Start menu on the computer, and select Search, then "For files of folders". Search for the name of the file you just saved.
Right click the file when it appears in your search results, and mouse over Open With. From the next sub-menu that appears, select "Choose Program," then select the program the file was made in (MS Word, MS Powerpoint, etc.). The file should open properly in that program.