System.ArgumentException: Value does not fall within the expected range

Hi,

I'm getting below exception for the code, where 'Project Description' is the field display name.

SPWeb oWebsite = SPContext.Current.Web;
SPList oList = oWebsite.Lists["Project Info"];
SPListItemCollection collItem = oList.GetItems("Project Description");
if (collItem.Count > 0)
{
    foreach (SPListItem oItem in collItem)
    {
        description = oItem["Project Description"].ToString();
    }
}

System.ArgumentException: Value does not fall within the expected range.
   at Microsoft.SharePoint.SPFieldMap.GetColumnNumber(String strFieldName, Boolean bThrow)
   at Microsoft.SharePoint.SPListItemCollection.GetColumnNumber(String groupName, Boolean bThrowException)
   at Microsoft.SharePoint.SPListItemCollection.GetRawValue(String fieldname, Int32 iIndex, Boolean bThrow)
   at Microsoft.SharePoint.SPListItem.GetValue(SPField fld, Int32 columnNumber, Boolean bRaw, Boolean bThrowException)
   at Microsoft.SharePoint.SPListItem.GetValue(String strName, Boolean bThrowException)
   at Microsoft.SharePoint.SPListItem.get_Item(String fieldName)

But this code works fine, where 'All Items' is the view.

SPWeb oWebsite = SPContext.Current.Web;
SPList oList = oWebsite.Lists["Project Info"];
SPListItemCollection collItem = oList.GetItems(oList.Views["All Items"] );
if(collItem.Count>0)
{
    foreach(SPListItem oItem in collItem)
    {
        description = oItem["Project Description"].ToString();
    }
}

It seems that there is some issue with field internal name. But why it works, when we use view to get list items?