do a check to see if daily episode has airdate before attempting a search.

NzbDrone.Core/IndexerSearch/NzbSearchService.cs

@@ -54,6 +54,11 @@ namespace NzbDrone.Core.IndexerSearch
 
             if (series.SeriesType == SeriesTypes.Daily)
             {
+                if (string.IsNullOrWhiteSpace(episode.AirDate))
+                {
+                    throw new InvalidOperationException("Daily episode is missing AirDate. Try to refresh series info.");
+                }
+
                 return SearchDaily(episode.SeriesId, DateTime.ParseExact(episode.AirDate, Episode.AIR_DATE_FORMAT, CultureInfo.InvariantCulture));
             }
 

NzbDrone.Core/Indexers/SyndicationFeedXmlReader.cs

@@ -72,7 +72,7 @@ namespace NzbDrone.Core.Indexers
             return dateVal;
         }
 
-        public void CheckForError()
+        private void CheckForError()
         {
             if (MoveToContent() == XmlNodeType.Element)
             {