Parser Error Message: Provider must implement the class 'System.Web.Security.RoleProvider'.

HI,
 
Everything was working fine the web application. This appeared while I ran the application.
: Parser Error Message: Provider must implement the class 'System.Web.Security.RoleProvider'.
I am not getting what is the issue. the first point I am not interested in role addition.
 
 <roleManager defaultProvider="AspNetSqlMembershipProvider">       <providers>         <clear />         <add connectionStringName="NewConnectionString" enablePasswordRetrieval="true" enablePasswordReset="false" requiresQuestionAndAnswer="true" requiresUniqueEmail="false" passwordFormat="Clear" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="5" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow=" ...