The issue looks to be caused by a conflict in our SCLogin code and your template's CSS. Can you try editing the /modules/mod_sclogin/tmpl/login.php file. Around line 68, you'll see:
echo '<div id="login-modal" class="sourcecoast modal hide fade" tabindex="-1" role="dialog" aria-labelledby="login-modalLabel" aria-hidden="true" style="display:none">';
Update that to:
echo '<div id="login-modal" class="sourcecoast modal fade" tabindex="-1" role="dialog" aria-labelledby="login-modalLabel" aria-hidden="true" style="display:none">';
The difference there is removing the word 'hide' from the class=".." section.
Please let me know if that helps get you going.
Thanks,
Alex