You missed a chunk of the quantity code. Just comment out this whole chunk instead of pieces of it:
Code:
<table width="100%" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2">
<font class="ProductDetailsTitle">{*{$lng.lbl_options}*}</font>
</td>
</tr>
<tr><td class="Line" height="1" colspan="2">[img]{$ImagesDir}/spacer.gif[/img]</td></tr>
<tr><td colspan="2"></td></tr>
{if $active_modules.Product_Options ne ""}
{ include file="modules/Product_Options/customer_options.tpl"}
{/if}
<tr>
<td height="25" width="30%">{*{$lng.lbl_quantity}*}{if $product.min_amount gt 1}
<font class="ProductDetailsTitle">{$lng.txt_need_min_amount|substitute:"items":$product.min_amount}</font>{/if}</td>
<td>
{if $config.General.unlimited_products eq "N" and ($product.avail le 0 or $product.avail lt $product.min_amount) and $variants eq ''}
<script type="text/javascript" language="JavaScript 1.2">
<!--
var min_avail = 1;
var avail = 0;
var product_avail = 0;
-->
</script>
{$lng.txt_out_of_stock}
{else}
{if $config.General.unlimited_products eq "Y"}
{assign var="mq" value=$config.Appearance.max_select_quantity}
{else}
{math equation="x/y" x=$config.Appearance.max_select_quantity y=$product.min_amount assign="tmp"}
{if $tmp<2}
{assign var="minamount" value=$product.min_amount}
{else}
{assign var="minamount" value=1}
{/if}
{math equation="min(maxquantity+minamount, productquantity+1)" assign="mq" maxquantity=$config.Appearance.max_select_quantity minamount=$minamount productquantity=$product.avail}
{/if}
{if $product.distribution eq "" and !($active_modules.Subscriptions ne "" and $subscription)}
{if $product.min_amount le 1}
{assign var="start_quantity" value=1}
{else}
{assign var="start_quantity" value=$product.min_amount}
{/if}
{if $config.General.unlimited_products eq "Y"}
{math equation="x+y" assign="mq" x=$mq y=$start_quantity}
{/if}
<font class="ProductDetailsTitle">1</font>{if $product.distribution ne ""}{$lng.txt_product_downloadable}{/if}
{/if}
{/if}
</td></tr>
<tr><td colspan="2">
<input type="hidden" name="mode" value="add" />
{include file="customer/main/product_prices.tpl"}
{if $config.General.unlimited_products eq "Y" or ($product.avail gt 0 and $product.avail ge $product.min_amount)}
{if $js_enabled}
{if $product.forsale ne "B"}
<table cellspacing="0" cellpadding="0">
<tr>
<td>{*{include file="buttons/add_to_cart.tpl" style="button" href="javascript: if(FormValidation()) document.orderform.submit();"}*}</td>
<td></td>
<td>
{*{if ($login ne "" || $config.Wishlist.add2wl_unlogged_user eq 'Y') && $active_modules.Wishlist ne ""}
{include file="customer/add2wl.tpl"}
{/if}*}
</td>
</tr>
</table>
{else}
{$lng.txt_pconf_product_is_bundled}
{/if}