diff --git a/hydrachain/app.py b/hydrachain/app.py
index a5c4f32..6f38d3a 100644
--- a/hydrachain/app.py
+++ b/hydrachain/app.py
@@ -24,7 +24,6 @@
 from pyethapp.console_service import Console
 from pyethapp.db_service import DBService
 from pyethapp.jsonrpc import JSONRPCServer
-from pygelf.handlers import GelfUdpHandler
 
 from hydrachain import __version__
 from hydrachain.hdc_service import ChainService
diff --git a/hydrachain/hdc_service.py b/hydrachain/hdc_service.py
index 25c3806..728a69b 100644
--- a/hydrachain/hdc_service.py
+++ b/hydrachain/hdc_service.py
@@ -9,6 +9,7 @@
 from ethereum.refcount_db import RefcountDB
 from ethereum.blocks import Block, VerificationFailed
 from ethereum.transactions import Transaction
+from ethereum import exceptions
 from devp2p.service import WiredService
 from ethereum import config as ethereum_config
 import gevent
@@ -296,7 +297,7 @@ def _link_block(self, t_block):
             log.debug('deserialized', elapsed='%.4fs' % elapsed, ts=time.time(),
                       gas_used=block.gas_used, gpsec=self.gpsec(block.gas_used, elapsed))
             assert block.header.check_pow()
-        except processblock.InvalidTransaction as e:
+        except exceptions.InvalidTransaction as e:
             log.warn('invalid transaction', block=t_block, error=e, FIXME='ban node')
             return
         except VerificationFailed as e:
diff --git a/hydrachain/native_contracts.py b/hydrachain/native_contracts.py
index 4d93508..a8e6161 100644
--- a/hydrachain/native_contracts.py
+++ b/hydrachain/native_contracts.py
@@ -41,6 +41,7 @@
 import ethereum.utils as utils
 import ethereum.vm as vm
 from ethereum import slogging
+from ethereum import exceptions
 from ethereum.transactions import Transaction
 from ethereum.utils import encode_int, zpad, big_endian_to_int, int_to_big_endian
 
@@ -574,7 +575,7 @@ def test_call(block, sender, to, data='', gasprice=0, value=0):
 
     try:
         success, output = processblock.apply_transaction(test_block, tx)
-    except processblock.InvalidTransaction as e:
+    except exceptions.InvalidTransaction as e:
         success = False
     assert block.state_root == state_root_before
     if success: