It looks like your languages/english/faq.php file was not created successfully upon upgrade.
The solution is to copy the faq.php file (mentioned above) from your archive, in to the same directory path on your forum install.
example:
ubbthreads-XXX.zip/ubbthreads-XXX/languages/english/faq.php
to
YOURDOMAIN dot com/ ... /languages/english/faq.php
