Thank you this is the right thing. There was a need of value change in "AspMaxRequestEntityAllowed" in Metabase.xml. I am writing what to do for the people who has the same problem.
Open MetaBase.xml which is located in c:\Windows\System32\Inetsrv find the line "AspMaxRequestEntityAllowed" and change it to "1073741824".
And restart the IIS (that's what I did.)
And it works without any problem. Thanks again.