diff --git a/setup/installer/linux/util.c b/setup/installer/linux/util.c
index dfbaaef62c..b06d6083c9 100644
--- a/setup/installer/linux/util.c
+++ b/setup/installer/linux/util.c
@@ -30,11 +30,12 @@ int report_libc_error(const char *msg) {
 }
 
 int pyobject_to_int(PyObject *res) {
-    int ret; PyObject *tmp;
-    tmp = PyNumber_Int(res);
-    if (tmp == NULL) ret = (PyObject_IsTrue(res)) ? 1 : 0;
-    else ret = (int)PyInt_AS_LONG(tmp);
-
+    int ret = 0; PyObject *tmp;
+    if (res != NULL) {
+        tmp = PyNumber_Int(res);
+        if (tmp == NULL) ret = (PyObject_IsTrue(res)) ? 1 : 0;
+        else ret = (int)PyInt_AS_LONG(tmp);
+    }
     return ret;
 }
 
diff --git a/src/calibre/ebooks/oeb/reader.py b/src/calibre/ebooks/oeb/reader.py
index 6c10436038..422252f73e 100644
--- a/src/calibre/ebooks/oeb/reader.py
+++ b/src/calibre/ebooks/oeb/reader.py
@@ -191,7 +191,11 @@ class OEBReader(object):
                         if not scheme and href not in known:
                             new.add(href)
                 elif item.media_type in OEB_STYLES:
-                    for url in cssutils.getUrls(item.data):
+                    try:
+                        urls = list(cssutils.getUrls(item.data))
+                    except:
+                        urls = []
+                    for url in urls:
                         href, _ = urldefrag(url)
                         href = item.abshref(urlnormalize(href))
                         scheme = urlparse(href).scheme
diff --git a/src/calibre/gui2/actions/store.py b/src/calibre/gui2/actions/store.py
index 9c30a9beb1..1f1130836c 100644
--- a/src/calibre/gui2/actions/store.py
+++ b/src/calibre/gui2/actions/store.py
@@ -53,7 +53,7 @@ class StoreAction(InterfaceAction):
         if self.gui.current_view() is self.gui.library_view:
             author = self.gui.library_view.model().authors(row)
             if author:
-                author = author.replace('|', ',')
+                author = author.replace('|', ' ')
         else:
             mi = self.gui.current_view().model().get_book_display_info(row)
             author = ' & '.join(mi.authors)