Error was, One of the input parameter was sending XML data to Report. Since any input in tag(<something>) is considered as potentially dangerous, It was throwing error. I need to disable this securuty check in aspx page's Register tag. and version change in web.configue :)
https://msdn.microsoft.com/en-us/library/vstudio/hh882339(v=vs.100).aspx,
http://www.asp.net/whitepapers/aspnet4/breaking-changes