diff --git a/lib/matplotlib/iruby.rb b/lib/matplotlib/iruby.rb
index 904989f..4c21b85 100644
--- a/lib/matplotlib/iruby.rb
+++ b/lib/matplotlib/iruby.rb
@@ -61,7 +61,7 @@ def execute_request(msg)
         rescue SystemExit
           content[:payload] << { source: :ask_exit }
         rescue Exception => e
-          content = error_message(e)
+          content = error_content(e)
           @session.send(:publish, :error, content)
         end
 
@@ -248,7 +248,7 @@ def show_figures(close=false)
                               execution_count: kernel.instance_variable_get(:@execution_count))
         end
       ensure
-        unless gcf.get_all_fig_managers.nil?
+        unless gcf.get_all_fig_managers.length == 0
           Matplotlib::Pyplot.close('all')
         end
       end