diff -r -U 3 minecraft\net\minecraft\network\EnumConnectionState.java minecraft_patched\net\minecraft\network\EnumConnectionState.java
--- minecraft\net\minecraft\network\EnumConnectionState.java
+++ minecraft_patched\net\minecraft\network\EnumConnectionState.java
@@ -323,7 +323,7 @@
          field_150764_e[i - -1] = enumconnectionstate;
 
          for(EnumPacketDirection enumpacketdirection : enumconnectionstate.field_179247_h.keySet()) {
-            for(Class<? extends Packet<?>> oclass : ((BiMap)enumconnectionstate.field_179247_h.get(enumpacketdirection)).values()) {
+            for(Class<? extends Packet<?>> oclass : enumconnectionstate.field_179247_h.get(enumpacketdirection).values()) {
                if (field_150761_f.containsKey(oclass) && field_150761_f.get(oclass) != enumconnectionstate) {
                   throw new Error("Packet " + oclass + " is already assigned to protocol " + field_150761_f.get(oclass) + " - can't reassign to " + enumconnectionstate);
                }