Help need : File Upload above 250 mb show error message

Hi,

       I am working on asp.net upload functionality. I need to upload files to  first server and then FTP.

       I have set the maxRequestLength="2097151" and also set the required properties in web.config.

       If i select above 250 mb file and submit immediately it show the "page can't  be load " error message. Minimum i need to upload 1 gb files.

       What are all the basic properties and needed property to handle this type of  large uploads.

       i am expecting your replay.

Thanks and Regards< ...