Laurent – are you on Mac or Windows? Which operating system version?
Bruce – could you open the java console on your Mac and see if there any error messages reported.
First you need to launch the java control panel. This has changed from earlier versions of Mac OSX – "To access the Java Control Panel, click the Java icon in the System Preferences panel. If the Java icon is not present (under the Other category) in System Preferences, you do not have an Oracle JRE installed."
Select Show java console in the control panel advanced tab. Open FF or Safari and browse to the svManager upload page. The console should pop-up. Try an upload. Please post anything that looks like an error message here or email me via the forum if it's too long to post.
SimpleViewer Support Team.