Notice messages – Getting property & undefined index

Please be kind and gentle – very new to all of this and don’t have much of a clue about coding!

I have begun to see these two notice messages appear when accessing a plugin (Wysija)

Notice: Trying to get property of non-object in /home/… …/public_html/lw2/wp-content/plugins/edit-flow/modules/editorial-metadata/editorial-metadata.php on line 634

Notice: Undefined index: post_type in /home/… … /public_html/lw2/wp-content/plugins/easy-media-gallery-pro/easy-media-gallery-pro.php on line 413

I did get two more that refered to The Events Calendar, but after today’s update, they’ve disappeared.

I’m thinking it’s something to do with the Edit Flow and Easy Media plugins not being able to write something in a file somewhere. I used Better WP Security to make a few changes, including (for a while) change the writeable status of wp-config.php and .htacess. These two files are now writeable again and were made non-writeable after the two plugins were installed.

I have tried completely deleting and reinstalling Edit Flow and Easy Media but no joy. Any suggestions?