Download large files error

Hi,
I am using the below code to download a file.If the file is more than 1mb its not downloading.It just stops the download.

string filename = System.IO.Path.GetFileName(filepath);

Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition","attachment; filename="+filename );

Response.TransmitFile(filepath); 
 





Any ideas!..
 
Thanks,
Sunil. 
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