Data source name not found and no default driver specified

I am using oracle 11g xpress edition and ASP.net I have got following error
ERROR [IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
My connection string is as follows**

<connectionStrings>
  <add name="APRConnStr" connectionString="Data Source=XE;Persist Security Info=True;User ID=dotnet;Password=dotnet;Unicode=True"
   providerName="System.Data.OracleClient" />
 </connectionStrings>

**
Microsoft ODBC administrator is showing the driver properly in both user and system dsn
Still unable to resolve the error

enter image description here

Pl help urgently.