Problem giving navbar round edges

[Tygerwoody]

I'm trying to edit the table of the navbar to give the edges a rounded look. I started on the top left corner, and for some reason I have a "box" around my rounded edge. http://www.guildclan.com If you look at the navbar, just look at the top left corner and you will see what i mean. Here is the portion of code from my navbar. Please show me what i need to change.

<!-- top nav buttons bar -->
<div align="center">
    <table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="0" border="0" width="100%" align="center" style="border-bottom-width:0px">
    <tr align="center">

<td width="15px"><img src="http://img217.imageshack.us/img217/9268/nwns0.gif"></td>
        <td class="vbmenu_control"><a href="http://www.guildclan.com">Home</a></td>

<td class="vbmenu_control"><a href="http://www.guildclan.com/vBulletin/newthread.php?do=form">Submit your Guild/Clan Application</a></td>

        <td class="vbmenu_control"><a href="profile.php?do=editusergroups$session[sessionurl]">Join your Guild/Clan's Usergroup!</a></td>

Help please