ClamWinPortableDBUpdate
ClamWinPortableDBUpdate has been tested on Windows XP SP2 and SP3. I have no idea what it will do on other versions of Windows.
To use ClamWinPortableDBUpdate, you will also need to have installed ClamWin Portable.
ClamWinPortableDBUpdate assumes you did a "normal" ClamWin Portable installation and did not change any of the default directory structures. If you changed anything (e.g., for use on a CD) you may not be able to use ClamWinPortableDBUpdate without source-code level changes.