fix for http://www.slightlymagic.net/forum/viewtopic.php?f=26&t=787&p=69769#p69769

src/main/java/forge/quest/data/QuestDataIO.java

@@ -63,6 +63,7 @@ public class QuestDataIO {
             InputStreamReader reader = new InputStreamReader(zin);
             while (reader.ready()) {
                 int len = reader.read(buf);
+                if (len == -1) { break; } // when end of stream was reached
                 xml.append(buf, 0, len);
             }