problem saving data in RSS Reader

[suho]

//here i hv to filter newsitems which i already hv in my database
// and save the rest. BUT i am getting some errors
// PLZ HELP

private void queryChannels()
{
int l=rssDataSet.Ch annel.Rows.Coun t;
foreach(rssData Set.ChannelRow currentChannel in rssDataSet.Chan nel.Rows)
{

System.Collecti ons.ArrayList result;
result = rssManager.proc essNewsFeed(cur rentChannel.URL );

foreach (RSSReader2.New sItem currentNewsItem in result)
{
string title = currentNewsItem .Title;

if (title.Length >= 50)
title = title.Substring (0, 49);

title.Replace(" '", "");

string filterExpressio n = "Title= '" + title + "'";

//i hv temporarily removed filtering
//System.Data.Dat aRow[] filterdNewsItem s= rssDataSet.News Item.Select(fil terExpression);
//PROBLEM IS HERE...!!!
//i am getting filterdNewsItem s Dimensions=0
//if (filterdNewsIte ms.Length != 0)
//{
rssDataSet.News ItemRow newRow = rssDataSet.News Item.NewNewsIte mRow();

newRow.Title = currentNewsItem .Title;
newRow.Link = currentNewsItem .Link;
newRow.Descript ion = currentNewsItem .Description;
newRow.ChannelI D = currentChannel. ChannelID;
newRow.DateAcqu ired = DateTime.Now;
newRow.NewsItem ID = ++l;

//if(newRow != null)
rssDataSet.News Item.AddNewsIte mRow(newRow);
// }
}
}
//PROBLEM HERE ALSO....!!!!whe n i removed the filtering
//ERROR IS :Cannot insert explicit value for identity column
// in table 'NewsItem' when IDENTITY_INSERT is set to OFF.
int rowsAffected = newsItemTableAd apter.Update(rs sDataSet);
// based on rowsaffected update status label

}