diff --git a/cosmoabc/ABC_functions.py b/cosmoabc/ABC_functions.py
index 53efa88..6f6308b 100644
--- a/cosmoabc/ABC_functions.py
+++ b/cosmoabc/ABC_functions.py
@@ -74,7 +74,7 @@ def read_input(filename):
     params['dist_dim'] = int(params_ini['dist_dim'][0])
     
     #functions
-    from distances import distance_GRBF
+    from .distances import distance_GRBF
     dispatcher = {'flat_prior': flat_prior, 
                   'gaussian_prior': gaussian_prior, 'beta_prior': beta_prior, 
                   'distance_quantiles': distance_quantiles, 
diff --git a/cosmoabc/ABC_sampler.py b/cosmoabc/ABC_sampler.py
index aa83d35..96c2b62 100644
--- a/cosmoabc/ABC_sampler.py
+++ b/cosmoabc/ABC_sampler.py
@@ -414,7 +414,8 @@ def UpdateWeights(self, W, previous_particle_system,
             indx = len(self.params['param_to_fit'])
             denominator = sum(W[i3]*multivariate_normal.pdf(
                               current_particle_system[i4][:indx], 
-                              previous_particle_system[i3][:indx], cov=cov1) 
+                              previous_particle_system[i3][:indx],
+                              cov=cov1, allow_singular=False) 
                               for i3 in range(len(W)))
 
             new_weights.append(nominator/denominator)
diff --git a/cosmoabc/bin/continue_ABC.py b/cosmoabc/bin/continue_ABC.py
index 1f78987..4d6d774 100644
--- a/cosmoabc/bin/continue_ABC.py
+++ b/cosmoabc/bin/continue_ABC.py
@@ -31,7 +31,7 @@
 """
 
 import argparse
-import imp
+import importlib.machinery as imp
 
 from cosmoabc.distances import distance_quantiles, distance_GRBF
 from cosmoabc.priors import flat_prior, gaussian_prior, beta_prior
@@ -45,7 +45,7 @@ def main(args):
     if user_input['path_to_obs'] == 'None':
         raise IOError('It is not possible to continue a process without determining a static data set.')    
 
-    m1 = imp.load_source(args.functions[:-3], args.functions)
+    m1 = imp.SourceFileLoader(args.functions[:-3], args.functions).load_module()
 
     user_input['simulation_func'] = getattr(m1, user_input['simulation_func'][0])
 
diff --git a/cosmoabc/bin/run_ABC.py b/cosmoabc/bin/run_ABC.py
index e22c7d3..f052060 100644
--- a/cosmoabc/bin/run_ABC.py
+++ b/cosmoabc/bin/run_ABC.py
@@ -31,7 +31,7 @@
 """
 
 import argparse
-import imp
+import importlib.machinery as imp
 
 from cosmoabc.distances import distance_quantiles, distance_GRBF
 from cosmoabc.priors import flat_prior, gaussian_prior, beta_prior
@@ -42,7 +42,7 @@
 def main( args ):
 
     user_input = read_input(args.input)
-    m1 = imp.load_source(args.functions[:-3], args.functions)
+    m1 = imp.SourceFileLoader(args.functions[:-3], args.functions).load_module()
 
     user_input['simulation_func'] = getattr(m1, user_input['simulation_func'][0])
 
diff --git a/setup.py b/setup.py
index be35b24..e274f13 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,6 @@ def readme():
                       'scipy>=1.7.0',
                       'statsmodels>=0.12.2',
                       'matplotlib>=3.4.2',
-                      'distribute',
                       'datetime'               
       ],
       scripts=['cosmoabc/bin/run_ABC.py', 'cosmoabc/bin/run_ABC_NumCosmo.py',