http://code.google.com/p/ocropus/issues/detail?id=365

diff --git a/setup.py b/setup.py
index c6ade25..a2ad6bf 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,10 @@ assert sys.version_info[0]==2 and sys.version_info[1]>=7,\
 from distutils.core import setup, Extension, Command
 from distutils.command.install_data import install_data
 
+import matplotlib
+matplotlib.use('Agg')
 from ocrolib import default
+
 modeldir = "models/"
 modelfiles = default.installable
 modelprefix = "http://iupr1.cs.uni-kl.de/~tmb/ocropus-models/"