I ran into the same problem, for others who want this the work; there is just a minor extra modification needed:
Change this
Code:
{if $config.Appearance.show_in_stock eq "Y" and $config.General.unlimited_products ne "Y" and $product.distribution eq ""}
<TR><TD width="30%">{$lng.lbl_quantity}</TD><TD nowrap><SPAN id="product_avail_txt">{if $product.avail gt 0}In Stock</SPAN>{else}Not Available{/if}</TD></TR>
to:
Code:
{if $config.Appearance.show_in_stock eq "Y" and $config.General.unlimited_products ne "Y" and $product.distribution eq ""}
<TR><TD width="30%">{$lng.lbl_quantity}</TD><TD nowrap> {if $product.avail gt 0}In Stock{else}Not Available{/if}</TD></TR>
That should do it