Error while customizing item added event receiver

Following error is generated at the time of updating an item in item added event receiver.

"System.Runtime.

InteropServices.COMException: 0x81020015The file PublishingImages/sample.jpg has been modified by..."

This type of issue will occur for following libraries:

• Document library
• Form library
• Wiki page library
• Picture Library
• Reports library
• Calendar list

 Following is the code to fix this issue:

public override void ItemAdded(SPItemEventProperties properties)

       {

           base.ItemAdded(properties);

           string strWebId = properties.Web.Url;

           string strListName = properties.List.Title;

           int intListId = properties.ListItemId;

           using (SPSite objSite = new SPSite(strWebId))

           {

               using (SPWeb objWeb = objSite.OpenWeb())

               {

                   EventFiringEnabled = false;

                   objWeb.AllowUnsafeUpdates = true;

                   SPList objList = objWeb.Lists.TryGetList(strListName);

                   SPListItem item = objList.GetItemById(intListId);

                   if (objList.ItemCount == 0)

                   {

                       item["Chapter"] = 1;

                   }

                   else

                   {

                       //Get max course value

                   }

                   item.SystemUpdate(false);

                   EventFiringEnabled = true;

                   objWeb.AllowUnsafeUpdates = false;

               }

           }

       }

Reference: http://sharepointconnoisseur.blogspot.in/2011/04/save-conflict-error-when-creating-list.html