Error while accessing CLOB Data

Hi, I am building an ASP.Net application in which I have to access a CLOB data from Oracle database. I have used the 'System.Data.OracleClient' namespace and while coding, the quick list gives all its objects and works fine as I got in sample codes. But when I run the application, I got this error message: "The type or namespace name 'System.Data.OracleClient' does not exist in the class or namespace 'System.Data' (are you missing an assembly reference?)" What is the reason and also send me the solution. How I can get the value of CLOB data type. Can I get this value from normal DataReader object. Plz reply urgently............