diff --git a/virtualsmartcard/src/vpicc/virtualsmartcard/SEutils.py b/virtualsmartcard/src/vpicc/virtualsmartcard/SEutils.py
index 6443c6f..ddf7cc7 100644
--- a/virtualsmartcard/src/vpicc/virtualsmartcard/SEutils.py
+++ b/virtualsmartcard/src/vpicc/virtualsmartcard/SEutils.py
@@ -19,7 +19,7 @@
 import TLVutils
 from time import time
 from random import seed, randint
-from virtualsmartcard.ConstantDefinitions import *
+from virtualsmartcard.ConstantDefinitions import CRT_TEMPLATE
 from virtualsmartcard.utils import inttostring, stringtoint
 from virtualsmartcard.SWutils import *
 
@@ -30,7 +30,9 @@ class ControlReferenceTemplate:
         @param type: Type of the CRT (HT, AT, KT, CCT, DST, CT-sym, CT-asym) 
         @param config: A string containing TLV encoded Security Environment parameters 
         """
-        if type not in (TEMPLATE_AT, TEMPLATE_HT, TEMPLATE_KAT, TEMPLATE_CCT, TEMPLATE_DST, TEMPLATE_CT):
+        if type not in (CRT_TEMPLATE["AT"], CRT_TEMPLATE["HT"],
+                        CRT_TEMPLATE["KAT"], CRT_TEMPLATE["CCT"],
+                        CRT_TEMPLATE["DST"], CRT_TEMPLATE["CT"]):
             raise ValueError, "Unknown control reference tag."
         else:
             self.type = type
diff --git a/virtualsmartcard/src/vpicc/virtualsmartcard/SmartcardSAM.py b/virtualsmartcard/src/vpicc/virtualsmartcard/SmartcardSAM.py
index 3b13431..1316369 100644
--- a/virtualsmartcard/src/vpicc/virtualsmartcard/SmartcardSAM.py
+++ b/virtualsmartcard/src/vpicc/virtualsmartcard/SmartcardSAM.py
@@ -20,7 +20,7 @@
 import random, struct, hashlib
 from pickle import dumps, loads
 
-import SmartcardFilesystem, TLVutils
+import TLVutils
 import virtualsmartcard.CryptoUtils as vsCrypto
 from virtualsmartcard.SWutils import SwError, SW
 from virtualsmartcard.utils import inttostring, stringtoint, hexdump, C_APDU
@@ -66,7 +66,7 @@ class CardContainer:
         self.cardNumber = cardNumber
         self.PIN = PIN
         self.FSkeys = {}
-        self.cipher = 0x01 #Algorithm reference for __get_referenced_algorithm(p1)
+        self.cipher = 0x01
         self.master_password = None
         self.master_key = None
         self.salt = None
@@ -385,8 +385,9 @@ class SAM(object):
 
 class PassportSAM(SAM):       
     def __init__(self, mf):
-        
-        ef_dg1 = virtualsmartcard.SmartcardFilesystem.walk(mf, "\x00\x04\x01\x01")
+        import virtualsmartcard.SmartcardFilesystem as vsFS  
+
+        ef_dg1 = vsFS.walk(mf, "\x00\x04\x01\x01")
         dg1 = ef_dg1.readbinary(5)
         self.mrz1 = dg1[:43]
         self.mrz2 = dg1[44:]