Cannot complete this action.

Please try again.   at Microsoft.SharePoint.Library.SPRequestInternalClass.PreInitServer(String bstrAbsoluteRequestUrl, String bstrServerRelativeUrl, Int32 lZone, Guid gApplicationId, Guid gSiteId, Guid gDatabaseId, String bstrDatabaseServer, String bstrDatabaseName, String bstrDatabaseUsername, String bstrDatabasePassword, Boolean fHostHeaderIsSiteName)
   at Microsoft.SharePoint.Library.SPRequest.PreInitServer(String bstrAbsoluteRequestUrl, String bstrServerRelativeUrl, Int32 lZone, Guid gApplicationId, Guid gSiteId, Guid gDatabaseId, String bstrDatabaseServer, String bstrDatabaseName, String bstrDatabaseUsername, String bstrDatabasePassword, Boolean fHostHeaderIsSiteName)