Change message for new users

Fix a bug : updating operations doesn't work

src/model/export/XMLExportEngine.cpp

@@ -50,7 +50,18 @@ bool XMLExportEngine::SaveAccounts()
 
     for(it=_accounts.begin(); it!=_accounts.end(); it++)
     {
-	account = _user->GetAccount(it->first);
+	try
+	{
+	    account = _user->GetAccount(it->first);
+	}
+	catch(User::AccountNotFound)
+	{
+	    account.id = it->first;
+	    account.name = "Unknown";
+	    account.blocked = false;
+	    account._virtual = false;
+	    account.hidden = false;
+	}
 
 	ESCAPE_CHARS(account.name);
 	ESCAPE_CHARS(account.number);