Hi Uday...
go  to Setup-->Develop-->Custom Setting-->click on Manage--->if data is available click on Delete Button  (or) no data means then leave it....try belo w example...Its working fine  here my custom settting :



<pre>
<apex:page controller="customSetting">
<apex:form >
    <apex:pageblock title="Content Of Custom Setting ">
        <apex:pageBlockSection >
            <apex:panelGrid columns="2">
                Name :
                <apex:inputText value="{!Name}"/>
                Phone :
                <apex:inputText value="{!Phone}"/>
            </apex:panelGrid>           
        </apex:pageBlockSection>
        <apex:commandButton value="Save" action="{!sav}"/>
    </apex:pageblock>
</apex:form>
</apex:page>
</pre>
-----------------------------------------------
<pre>
public class customSetting { 
    public String Name{get;set;}
    public String loc{get;set;}
    public Integer Phone {get;set;}
    Id memId;
    public List<HirachicalCst__c> hcsList {get;set;}
    public customSetting () {
       
    }
    public void sav() {
        HirachicalCst__c hcstn= new HirachicalCst__c();
        hcstn.Id=memId;
        hcstn.Name__c = Name;
        hcstn.Phone__c = Phone;
        insert hcstn;
    }          
}
</pre>
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Output:



Thanks,
Rockzz