diff --git a/python-package/xgboost/core.py b/python-package/xgboost/core.py
index 74170ea84..b528e2800 100644
--- a/python-package/xgboost/core.py
+++ b/python-package/xgboost/core.py
@@ -220,7 +220,7 @@ class DMatrix(object):
             self._init_from_csr(data)
         elif isinstance(data, scipy.sparse.csc_matrix):
             self._init_from_csc(data)
-        elif isinstance(data, np.ndarray) and len(data.shape) == 2:
+        elif isinstance(data, np.ndarray):
             self._init_from_npy2d(data, missing)
         else:
             try:
@@ -278,6 +278,8 @@ class DMatrix(object):
         """
         Initialize data from a 2-D numpy matrix.
         """
+        if len(mat.shape) != 2:
+            raise ValueError('Input numpy.ndarray must be 2 dimensional')
         data = np.array(mat.reshape(mat.size), dtype=np.float32)
         self.handle = ctypes.c_void_p()
         _check_call(_LIB.XGDMatrixCreateFromMat(data.ctypes.data_as(ctypes.POINTER(ctypes.c_float)),
@@ -792,11 +794,11 @@ class Booster(object):
         fname : string or a memory buffer
             Input file name or memory buffer(see also save_raw)
         """
-        if isinstance(fname, str):  # assume file name
+        if isinstance(fname, STRING_TYPES):  # assume file name
             if os.path.exists(fname):
                 _LIB.XGBoosterLoadModel(self.handle, c_str(fname))
             else:
-                raise ValueError("No such file: {0}")
+                raise ValueError("No such file: {0}".format(fname))
         else:
             buf = fname
             length = ctypes.c_ulong(len(buf))
@@ -851,6 +853,8 @@ class Booster(object):
                                                             ctypes.byref(length),
                                                             ctypes.byref(sarr)))
         else:
+            if fmap != '' and not os.path.exists(fmap):
+                raise ValueError("No such file: {0}".format(fmap))
             _check_call(_LIB.XGBoosterDumpModel(self.handle,
                                                 c_str(fmap),
                                                 int(with_stats),
diff --git a/tests/python/test_basic.py b/tests/python/test_basic.py
index 404d4354f..e7c0629ca 100644
--- a/tests/python/test_basic.py
+++ b/tests/python/test_basic.py
@@ -83,6 +83,31 @@ class TestBasic(unittest.TestCase):
         self.assertRaises(ValueError, xgb.Booster,
                           model_file='incorrect_path')
 
+        self.assertRaises(ValueError, xgb.Booster,
+                          model_file=u'不正なパス')
+
+    def test_dmatrix_numpy_init(self):
+        data = np.random.randn(5, 5)
+        dm = xgb.DMatrix(data)
+        assert dm.num_row() == 5
+        assert dm.num_col() == 5
+
+        data = np.matrix([[1, 2], [3, 4]])
+        dm = xgb.DMatrix(data)
+        assert dm.num_row() == 2
+        assert dm.num_col() == 2
+
+        # 0d array
+        self.assertRaises(ValueError, xgb.DMatrix, np.array(1))
+        # 1d array
+        self.assertRaises(ValueError, xgb.DMatrix, np.array([1, 2, 3]))
+        # 3d array
+        data = np.random.randn(5, 5, 5)
+        self.assertRaises(ValueError, xgb.DMatrix, data)
+        # object dtype
+        data = np.array([['a', 'b'], ['c', 'd']])
+        self.assertRaises(ValueError, xgb.DMatrix, data)
+
     def test_plotting(self):
         bst2 = xgb.Booster(model_file='xgb.model')
         # plotting
@@ -127,4 +152,3 @@ class TestBasic(unittest.TestCase):
         assert isinstance(g, Digraph)
         ax = xgb.plot_tree(bst2, num_trees=0)
         assert isinstance(ax, Axes)
-