Radio buttons floating on my firefox but not on my friends firefox

Radio buttons floating on my firefox but not on my friends firefox

I'm using this CSS code to display several radio buttons on the same line:
#new .radioLine
{
width: 400px;
float: left;
}
#new .radio
{
width: 80px;
height: 20px;
float: left;
}
.radioLine surrounds the .radio divs, for example:
<div class="radioLine">
<div class="radio"><input type="radio" name="radio" value="one">One</div>
<div class="radio"><input type="radio" name="radio" value="two">Two</div>
<div class="radio"><input type="radio" name="radio"
value="three">Three</div>
</div>
On my firefox browser these all appear on the same line, however the same
page on my friends computer, also under firefox, appear each on a separate
line.