Yea I had a look at your site earlier.
You need to check as I see you have a custom skin, that within
customer/main/product_details.tpl
You do have this:
{if $product.appearance.has_market_price && $product.appearance.market_price_discount gt 0}
<td align="right" valign="top">
<div class="save-percent-container">
<div class="save" id="save_percent_box">
<span id="save_percent">{$product.appearance.market_pric e_discount}</span>%
</div>
</div>
</td>
{/if}
The only reason I suppose it would stop working is some edits somewhere on your templates, or maybe some custom mod maybe.