The gallery whose link you posted above (your 'Grands formats' gallery) uses SimpleViewer-Standard v2.3.2 and seems to display and function fine. If you do not see this yourself, try clearing your browser's cache before reloading your web page to ensure that your browser is fetching and using the most recent gallery files from your web server.
Your 'Moyens formats' gallery displays the 'Flickr PhotoSet Not Found' message because it uses the SWF file from the SimpleViewer-Pro v2.0.2 package.
You will need to upgrade all your Flickr-based galleries to the latest version of SimpleViewer for your Flickr images to be displayed.
A quick fix for your 'Moyens formats' gallery would be to replace the http://larenecieliste.free.fr/moyensformats/simpleviewer.swf file on your web server with the 'simpleviewer.swf' file from either the SimpleViewer-Standard v2.3.2 or SimpleViewer-Pro v2.3.2 zip package ('simpleviewer_2.3.2/web/svcore/swf/simpleviewer.swf').
However, please note that this gallery will not benefit from Universal Playback until you upgrade it (using svBuilder and the new style embedding code) to use the 'svcore' folder (which was introduced in SimpleViewer v2.1.0) rather than just a single SWF file.
SimpleViewer Support Team