Timeout occurs when downloading files from the server

Hi,

I have an application whch downloads files from a server using WinINet.dll
with HTTP.
When download files such as 1mb in size it works fine.
But when download files with size about 25mb a timeout occurs and returns
error code 12002

Following are set in IE,

DECLARE INTEGER InternetSetOption IN WININET.DLL INTEGER, INTEGER, INTEGER
@, INTEGER

dwTimeoutSecs = 600*1000

InternetSetOption(hIPSession,INTERNET_OPTION_CONNE CT_TIMEOUT,@dwTimeoutSecs,4)

InternetSetOption(hIPSession,INTERNET_OPTION_DATA_ RECEIVE_TIMEOUT,@dwTimeOutSecs,4)

InternetSetOption(hIPSession,INTERNET_OPTION_DATA_ SEND_TIMEOUT,@dwTimeOutSecs,4)

Is there anything more need to be set?
or
Is there any other method to over come this error ?