[ThickBox] n00b question about css on the box

[ThickBox] n00b question about css on the box

I have this div for my thickbox:

<div id="TBcontent" style="display: none;"><p id="TB-output"></p>
<p>Click the below button to close this box</p>
<p><input type="button" id="TBcancel" class="button" value="Close window" /></p>
</div>

this is being called by:

$("p#TB-output").text("Please supply your name!");
tb_show('Error','TB_inline?height=130&amp;width=300&amp;inlineId=TBcontent');
hasError = true;

Ther class for the button doesn't appear, it is just a plain with white text button, any clues?