The following resource locales are included with ActiveReports in the ActiveReports.FlashViewer.Resources.swf file (located in the Deployment folder):
You can create your own localization resources and send them to GrapeCity support for signing.
WebViewer.FlashViewerOptions.ResourceLocale = Request.Form["LanguageDropDownList"];
WebViewer.FlashViewerOptions.ResourceLocale = Request.Form("LanguageDropDownList")