i have an error

Error 3 The type or namespace name 'CheckSurveyExistCompletedEventArgs' does not exist in the namespace 'VotingPanel2.ServiceReference3' (are you missing an assembly reference?) C:\Users\Iram\Documents\Visual Studio 2008\Projects\VotingPanel2\VotingPanel2\CreateSurv eyForm.xaml.cs 37 93 VotingPanel2


Code:
void client_CheckSurveyExistCompleted(object sender, VotingPanel2.ServiceReference3.CheckSurveyExistCompletedEventArgs e) 
{ 
int a; 
a = e.Result; 

}
please help me

i add reference too