Don't worry about the jargon in the above title. You can safely ignore it. We will walk you through the process.
Start Excel with no workbooks loaded.
Press Alt-F11
to open the Visual Basic window, which will look something like this:

From this window, select Tools
| References.... A
dialog box like the following should appear. 
Make sure that the four boxes that you see above are checked.
Uncheck any boxes labeled MISSING.
Restart your computer, load Excel, then try to run a Wizard. If you still encounter errors, go on to the next step.
Microsoft has a knowledge base article on this problem at their web site. There are also numerous references to the solution in Internet chat groups.