Hi there,
Without a link to your site it is quite hard for us to provide the best solution due to so many variables. We try to provide file names and line numbers for code changes and if changes have already been made then our advice may be incorrect.
Can you please post a link to the problem and we will do our best to assist you.
The initial call comes from index.php...<?php if ($this->countModules('login')) : ?>
<?php if ($user->guest) : ?>
<a href="#" id="lock-button" rel="rokbox[240 210][module=login-module]"><span id="lock-icon" class="login"></span><span><?php echo JText::_('LOGIN'); ?></span></a>
<?php else : ?>
<a href="#" id="lock-button" rel="rokbox[240 210][module=login-module]"><span id="lock-icon"></span><span><?php echo JText::_('LOGOUT'); ?></span></a>
<?php endif; ?>
<?php endif; ?>
Which in turn shows that the code is in the language file language/en-GB/en-GB.tpl_rt_affinity_j15.ini
If this resolves your problem then please edit your first post in this thread by adding SOLVED at the start of the title and then select the green tick icon. This lets the moderators know that it can be moved to the solved section.
Thanks for your cooperation 
Thanks