I finally created a Windows-Installer for the Stock Quotes Add-In for Excel 2007 (see article here).
For more details and instructions how to use the add-in please check out the article I have written.
IMPORTANT: Before using the add-in you should check if the installation has been executed correctly. Open the Excel 2007 options dialog and click the menu item Add-Ins. The list active add-ins should contain the „Parago.de Stock Quotes Function Add-In“ (COM-Add-In) as well as the „Parago.de Stock Quotes UI Add-In“ (COM-Add-In). Then open the „Excel-Add-In“ dialog by pressing the button on the Add-Ins dialog window (see button on the bottom of the dialog). Then check if the Add-In „ParagoStockQuote.Functions“ is available in the list and is marked. If not add it to the list and mark it.