Unfortunately, the version available for downloading from the official website of iSkysoft Video Converter requires the following OSX: Mac OS X 10.7 10.8, 10.9 Mavericks, 10.10 Yosemite and 10.11 El Capitan.
As you can see the minimum required version for iSkysoft Video Converter to work is OSX 10.7 which is Lion. Access the application's page at Mac Informer and choose another version from the list. That might be compatible with OS X 10.6.8 Snow Leopard.
