Fixed context expansion bug for new corpora

Change-Id: Id56324f94ef9a85815b38479f289f57c7ffd58b6
diff --git a/Errorcodes b/Errorcodes
index bb412dd..62b3e2f 100644
--- a/Errorcodes
+++ b/Errorcodes
@@ -7,6 +7,7 @@
 610: "Missing request parameters"
 620: "Unable to generate JSON"
 621: "Unable to parse JSON"
+651: "Unable to extend context"
 680: "Server is up and running!"
 681: "Document was added successfully", document id
 682: "Response time exceeded"