--- chaosreader.orig	2010-07-23 11:18:46.000000000 +0300
+++ chaosreader	2010-07-23 11:21:34.000000000 +0300
@@ -4028,7 +4028,11 @@
 	   ### This causes the replay program to pause
 	   print REPLAY "ms($timediff1);\n";
 	}
-	$speed = sprintf("%.2f",$bytes / (1024 * $duration));
+	if ( $duration > 0 ) {
+		$speed = sprintf("%.2f",$bytes / (1024 * $duration));
+	} else {
+		$speed = "unknown";
+	}
 	print REPLAY "print \"\n\n" .
 	 "Summary: $duration2 seconds, $bytes bytes, $speed Kb/sec\\n\";";
 	close REPLAY;