Label not being translated --> Possible fix: Transposing the t() and variable_get() functions

In this version, you are using the following code throughout:
variable_get('scroll_to_top_label', t('Back to top'))

it should be:
t(variable_get('scroll_to_top_label', 'Back to top'))

Take a look at http://drupal.org/node/299085.

Thanks for an awesome module!