>>I right click on the File and see the Summary tab properties. These are the properties I was talking about.
>>
>>Try it yourself with any Word file.
>
>I don't have DBF files here, would you please check if there is Summary tab for them as well?

There is no "Custom" tab for a (free) DBF's "Properties".

UPDATE: The following from Windows (Vista) Help:
"You cannot add or modify the file properties of some types of files. For example, you can add or modify the properties of Microsoft Office documents and Searches, but you can't add or modify the properties of TXT or RTF files."