Byblos problem – I think

I have tried to update my site which uses the Byblos theme several times and each time updating the Byblos theme causes the site to crash and both a warning and a fatal error message appears. Both messages seem to be looking for a file named /home…twentytwelve/inc/templates-tags.php which is not in the ../inc/ directory. Here are the messages:

Warning: require(/home/cliffpa/public_html/wp-content/themes/twentytwelve/inc/template-tags.php): failed to open stream: No such file or directory in /home/cliffpa/public_html/wp-content/themes/byblos/functions.php on line 51

Fatal error: require(): Failed opening required ‘/home/cliffpa/public_html/wp-content/themes/twentytwelve/inc/template-tags.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/cliffpa/public_html/wp-content/themes/byblos/functions.php on line 51

Can anyone tell me why the messages refer to a file that isn’t there and how I might fix this problem?

Thanks