diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index 6ffd41ed9c..464acbe0e0 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -183,7 +183,12 @@ class CSSFlattener(object):
                 elif value <= slineh:
                     cssdict[property] = "%0.5fem" % (dlineh / fsize)
                 else:
-                    value = round(value / slineh) * dlineh
+                    try:
+                        value = round(value / slineh) * dlineh
+                    except:
+                        self.oeb.logger.warning(
+                                'Invalid length:', value)
+                        value = 0.0
                     cssdict[property] = "%0.5fem" % (value / fsize)
 
     def flatten_node(self, node, stylizer, names, styles, psize, left=0):
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index b872b033d3..f976d72fee 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -129,7 +129,12 @@ class Adder(QObject):
             mi = MetaInformation('', [_('Unknown')])
             self.critical[name] = open(opf, 'rb').read().decode('utf-8', 'replace')
         else:
-            mi = MetaInformation(OPF(opf))
+            try:
+                mi = MetaInformation(OPF(opf))
+            except:
+                import traceback
+                mi = MetaInformation('', [_('Unknown')])
+                self.critical[name] = traceback.format_exc()
         if not mi.title:
             mi.title = os.path.splitext(name)[0]
         mi.title = mi.title if isinstance(mi.title, unicode) else \
diff --git a/src/calibre/manual/templates/layout.html b/src/calibre/manual/templates/layout.html
index 3564357684..606fc69386 100644
--- a/src/calibre/manual/templates/layout.html
+++ b/src/calibre/manual/templates/layout.html
@@ -1,6 +1,8 @@
 {% extends "!layout.html" %}
 {% block sidebarlogo %}
-{{ super() }}
+        <p class="logo">
+            <a href="http://calibre.kovidgoyal.net"><img class="logo" src="{{ pathto('_static/' + logo, 1) }}" alt="Logo"/></a>
+        </p>
          <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
                <input type="hidden" name="cmd" value="_s-xclick" />
                <input type="hidden" name="hosted_button_id" value="3028915" />