This is the HTML that generates the New Reply button.
<td style="padding-right: 3px;">
<table class="t_standard">
<tr>
<td class="tdheader">
<a style="text-decoration: none;" href="xxxx" rel="nofollow">New Reply</a>
</td>
</tr>
</table>
</td>
So you can see there is some padding in the template itself, specified at 3px. Then you have the t_standard class for the table that holds the button, and the tdheader class for the actual button.
The padding-right: 3px; should be giving you the space between the buttons. I'd check the source of your page and make sure that is there and hasn't been removed with any alterations.
