Try updating manually instead. I guess either the version is somehow mixed up in the wordpress updater, or something went wrong during the update. Manual update should resolve that.
I am seeing the issue now in the error report, you are using a custom folder for the plugin: /wp-content/plugins/ajax-search-pro 4.20.7/
That is a big no-no, plugins should be in their appropriate folders. I strongly recommend comletely uninstalling and removing this folder, and installing the plugin via the plugin manager, so the correct plugin folder is used. That explains the missing arrows as well.