Can't update variables/stock…screen goes blank, no updates!!

My woocommerce store is down because the “in stock” variable won’t update now that I have switched to Virtue theme. Actually, NONE of my variables will update/publish for any of my products. Admin/backend page looks great, click to “update” takes me to a totally blank screen. When I return to the admin page, the old variable remains unchanged.
Error log:
PHP Fatal error: Call to undefined method WC_Cache_Helper::get_transient_version() in /home2/foreclq0/public_html/wp-content/plugins/woocommerce/includes/wc-template-functions.php on line 1369

I don’t read code. Some help????