diff -aur blam-1.6.1-orig/src/FeedUpdater.cs blam-1.6.1/src/FeedUpdater.cs
--- blam-1.6.1-orig/src/FeedUpdater.cs	2004-10-20 20:21:46.000000000 -0400
+++ blam-1.6.1/src/FeedUpdater.cs	2005-05-07 11:23:01.000000000 -0400
@@ -22,9 +22,14 @@
 		string lastModified;
 		string eTag;
 
-		WebRequest req = WebRequest.Create(channel.Url);
-		req.Headers.Add("If-Modified-Since", channel.LastModified);
-		req.Headers.Add("If-None-Match", channel.ETag);
+		HttpWebRequest req = (HttpWebRequest) WebRequest.Create(channel.Url);
+		if (channel.LastModified != "") {
+			req.IfModifiedSince = DateTime.Parse(channel.LastModified);
+		}
+
+		if (channel.ETag != "") {
+			req.Headers.Add("If-None-Match", channel.ETag);
+		}
 	
 		req.Timeout = 20000;
 		WebResponse res = null;