hi, i did some testing on Windows XP-SP3 and without QuickViewPlus:
First i correctly installed a full version of Excel 2007 and of Outlook 2007. The latter is a prerequisite (system requirement) for the XP-PreviewHandlersPack to work! Then i correctly installed the XP-PreviewHandlersPack. The following screenshot makes it clear, a Preview Handler for XLS files is installed (see the top entry "MS Office Excel-Vorschau", this was created automatically by the installation of Excel 2007!) whereas no Preview Handler for MSG files is installed by the installation of a full version of Outlook 2007 (there is no such 
entry as "MS Office Outlook E-Mails-Vorschau"!).
With the above settings, i can preview XLS files...
...but MSG files dont work in the viewer pane. You could tell that the viewer pane tries to load the MSG file (and tries to display/preview it) .. but the total result is zilch. Nada. Nothing.
While it is obvious that you need Excel on your XP-system to be able to preview XLS-files, having Outlook 2007 on your XP-system will not let you preview MSG-files, for 2 independent reasons:
- Azar's XP handlers do not officially support MSG files (yet).
- As outlined above, such a thing as "MS Office Outlook E-Mails-Vorschau" is not being installed. At least not on a XP-system.
Now what happens when we uninstall all MS Office 2007 stuff?
The "MS Office Excel-Vorschau" handler vanishes and previewing Excel files is not possible anymore "although" XLS is listed in the following dialogue:
Summary:
If someone wants to preview MSG files from within Dopus (i.e. in the Dopus viewer pane), he/she
ALT1: must install WinVista (or Win7) (with?without? Outlook 2007+), or
ALT2: must install QuickViewPlus (on WinXP, WinVista, Win7) without any Outlook 2007+