diff --git a/src/IDF/Scm.php b/src/IDF/Scm.php
index 9e8de2d..8ee8c28 100644
--- a/src/IDF/Scm.php
+++ b/src/IDF/Scm.php
@@ -55,6 +55,9 @@ class IDF_Scm
         $cache = Pluf_Cache::factory();
         if (null === ($res=$cache->get($key))) {
             $ll = exec($command, $output, $return);
+            if ($return != 0) {
+                throw new IDF_Scm_Exception(sprintf('Error when running command: "%s", return code: %d', $command, $return));
+            }
             $cache->set($key, array($ll, $return, $output));
         } else {
             list($ll, $return, $output) = $res;
diff --git a/src/IDF/Scm/Exception.php b/src/IDF/Scm/Exception.php
new file mode 100644
index 0000000..eae2fd6
--- /dev/null
+++ b/src/IDF/Scm/Exception.php
@@ -0,0 +1,26 @@
+<?php
+/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+# ***** BEGIN LICENSE BLOCK *****
+# This file is part of InDefero, an open source project management application.
+# Copyright (C) 2008 Céondo Ltd and contributors.
+#
+# InDefero is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# InDefero is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#
+# ***** END LICENSE BLOCK ***** */
+
+class IDF_Scm_Exception extends Exception
+{
+}
\ No newline at end of file