The issue is from the following style in your template:
.row-fluid {
margin-left: -15px;
margin-right: -15px;
}
That's basically saying that there can't be enough room in our social buttons element to show in one row. That's coming from this file:
/templates/socialize/local/css/legacy-grid.css
A quick and easy fix would be to add the following CSS to counter-act the one above (so that it only targets our login module, and doesn't affect anything else):
.sourcecoast .row-fluid {
margin: 0 15px 0 15px;
}
I hope that helps, but should you need anything else, just let us know.
Thanks,
Alex