I am getting this error on a VF page :

This page is redirected from another controller class : The details are coming on the URL but on the page it is displaying error as :Page DetailController does not exist 

External Controller Class : Method :

public PageReference SaveChanges()

{
String OppId = ApexPages.currentPage().getParameters().get('Id');
Splits__c LitOrd = new Splits__c();
DSObj = new List<Splits__c>();
LitOrd.Opportunity__c= Opp.id ;
DSObj.add(LitOrd);
insert DSObj;
insert OppTeam;
PageReference pageRef = new PageReference('/apex/DetailController?Id='+opp.Id);
return pageRef;

}

--------------------------------------

VF page :

<apex:page controller="DetailController" tabstyle="Opportunity">
<apex:form >
<apex:pageBlock title="Region Details">
<apex:pageBlockTable value="{!wrappers}" var="wrapper" id="wtable">
<apex:column headerValue="Ident">
<apex:outputText value="{!wrapper.ident}"/>
</apex:column>
<apex:column headerValue="Region">
<apex:inputField value="{!wrapper.MSalesO.Region__c}"/>
</apex:column>
</apex:pageBlockTable>
<apex:commandButton value="Save" action="{!save}"/>
</apex:pageBlock>
</apex:form>
</apex:page>

--------------------------------------

Controller Class :

public class DetailController
{

public List<SOWrapper> wrappers {get; set;}

public static Integer addCount {get; set;}
private Integer nextIdent=0;

public DetailController()
{
wrappers=new List<SOWrapper>();
for (Integer idx=0; idx<5; idx++)
{
wrappers.add(new SOWrapper(nextIdent++));
}
}
public void addRows()
{
for (Integer idx=0; idx<addCount; idx++)
{
wrappers.add(new SOWrapper(nextIdent++));
}
}

public PageReference save()
{
List<Order__c> MSO=new List<Order__c>();
for (SOWrapper wrap : wrappers)
{
MSO.add(wrap.MSalesO);
}

insert MSO;

return new PageReference('/' + Schema.getGlobalDescribe().get('Order__c').getDescribe().getKeyPrefix() + '/o');
}

public PageReference SaveDS()

{
return null;
}
public class SOWrapper
{
public Order__c MSalesO {get; private set;}
public Integer ident {get; private set;}

public SOWrapper(Integer inIdent)
{
ident=inIdent;
MSalesO=new Order__c(Opportunity__c='006f0000003afa5' + ident);
}
}

}