I recently have been hit by this problem several times. I am using MS Office 2003, and people are sending me files from Office 2007 (or 2010). I downloaded and installed the Microsoft conversion tools from the MS web site.

After Googling a bit, I finally found a useful suggestion. You need to re-register the OLE32.DLL file, as described in this article from Microsoft.

1. Close any applications that are running.
    
2. Open an elevated command prompt. To do this, click Start , click All Programs , click Accessories , right-click Command Prompt , and then click Run as administrator . If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
    
3. Type the following:
   regsvr32 %SystemRoot%\system32\ole32.dll and then click OK.
    
4. When you receive the message  "DllRegisterServer in ole32.dll succeeded", click OK.

Last modified: November 28, 2011