Problem On Running Replication On Pocket Pc

hi i tried to view a replication on a pocket pc app that i created. and i used the following code

private void Sync()
{
public string AppPath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase);
SqlCeReplication repl = new SqlCeReplication();

repl.InternetUrl = @"http://naomi/sqlmobile/sqlcesa30.dll";
repl.Publisher = @"Naomi";
repl.PublisherDatabase = @"SQLMobile";
repl.PublisherSecurityMode = SecurityType.DBAuthentication;
repl.PublisherLogin = @"sa";
repl.PublisherPassword = @"<...>";
repl.Publication = @"SQLMobile";
repl.Subscriber = @"SQLMobile";
repl.SubscriberConnectionString = @"Data Source=""" + AppPath + @"SqlMobile.sdf"";Max Database Size=128;Default Lock Escalation =100;";
try
{
repl.AddSubscription(AddOption.ExistingDatabase);
repl.Synchronize();
}
catch (SqlCeException e)
{
MessageBox.Show(e.ToString());
}

when i run it i keep on getting the error:
The SQL Mobile Subscription already exists. Publisher, PublisherDatabase, and Publication for this subscription should be different from any existing subscription.

However, i can still view the contents of the datagrid that refers to the database subscription.

1. What should i do in order to stop getting the error above?
2. If i edit the contents of the datagrid in the pocket pc app how will i update the replication in the sql server? thanks