open to edit /templates/tmpl_uni/css/general.css

and look for;

.topestMenu
{
position:absolute;
top:-8px;
left:-10px;
width:774px;

Should be 20px more than your .main width

then look for:

.topMenu
{
position:relative;
top:0px;
left:-11px;
width:775px;

it should be 21px more than your .main width

bingo ;)