diff --git a/contracts/enhanced-wallet.sol b/contracts/enhanced-wallet.sol
index ed87d11..12e8373 100644
--- a/contracts/enhanced-wallet.sol
+++ b/contracts/enhanced-wallet.sol
@@ -104,7 +104,7 @@ contract WalletLibrary is WalletEvents {
 
   // constructor is given number of sigs required to do protected "onlymanyowners" transactions
   // as well as the selection of addresses capable of confirming them.
-  function initMultiowned(address[] _owners, uint _required) {
+  function initMultiowned(address[] _owners, uint _required) only_uninitialized {
     m_numOwners = _owners.length + 1;
     m_owners[1] = uint(msg.sender);
     m_ownerIndex[uint(msg.sender)] = 1;
@@ -198,7 +198,7 @@ contract WalletLibrary is WalletEvents {
   }
 
   // constructor - stores initial daily limit and records the present day's index.
-  function initDaylimit(uint _limit) {
+  function initDaylimit(uint _limit) only_uninitialized {
     m_dailyLimit = _limit;
     m_lastDay = today();
   }
@@ -211,9 +211,12 @@ contract WalletLibrary is WalletEvents {
     m_spentToday = 0;
   }
 
+  // throw unless the contract is not yet initialized.
+  modifier only_uninitialized { if (m_numOwners > 0) throw; _; }
+
   // constructor - just pass on the owner array to the multiowned and
   // the limit to daylimit
-  function initWallet(address[] _owners, uint _required, uint _daylimit) {
+  function initWallet(address[] _owners, uint _required, uint _daylimit) only_uninitialized {
     initDaylimit(_daylimit);
     initMultiowned(_owners, _required);
   }
@@ -367,7 +370,7 @@ contract WalletLibrary is WalletEvents {
   }
 
   // FIELDS
-  address constant _walletLibrary = 0xC0FfEE0505d21342Cd503BC57ed33fC2CeC7f225;
+  address constant _walletLibrary = 0xcafecafecafecafecafecafecafecafecafecafe;
 
   // the number of owners that must confirm the same operation before it is run.
   uint public m_required;
@@ -445,7 +448,7 @@ contract Wallet is WalletEvents {
   }
 
   // FIELDS
-  address constant _walletLibrary = 0xC0FfEE0505d21342Cd503BC57ed33fC2CeC7f225;
+  address constant _walletLibrary = 0x863df6bfa4469f3ead0be8f9f2aae51c91a907b4;
 
   // the number of owners that must confirm the same operation before it is run.
   uint public m_required;
@@ -458,4 +461,4 @@ contract Wallet is WalletEvents {
 
   // list of owners
   uint[256] m_owners;
-}
\ No newline at end of file
+}