Hi all. There is a problem with my new site.

When I took the site from offline to online, these two errors have appeared on the page of the gallery:

Notice: Undefined variable: language_code in /home2/papegn/public_html/wp-content/plugins/wp-simpleviewer/wp-simpleviewer.php on line 246

Notice: Undefined variable: seo_content in /home2/papegn/public_html/wp-content/plugins/wp-simpleviewer/wp-simpleviewer.php on line 251

What causes?
Can i fix it?

Thanks in advance for the answers.