Replace:
* tpl_button('subscription') with tpl_button('subscribe')
* tpl_actionlink('subscription') with tpl_actionlink('subscribe')
Should be around ~
Line228.
If you are running an older version of arctic, replace all occurrences of tpl_actionlink('unsubscribe') and/or tpl_button('unsubscribe') with tpl_actionlink('subscribe') and/or tpl_button('subscribe') because there is no 'unsubscribe' action anymore. The 'subscribe' page is providing a menu for both unsubscribe and subscribe since Anteater.