Hi,

Please refer to http://www.ajaxuploader.com/large-file-upload-iis-asp-net.htm  and set the "maxAllowedContentLength" setting from IIS directly instead of set in web.config. you also can find a debug file at the bottom of this page, it using the nromal asp.net upload control, you can try that file with a 30 MB file, if it gets problem too, that  means you did not set the large file upload settings correct for your site.

regards,

Ken