Hi Monaghan,
As long as I posted in the wrong section (I was not sure though where to post this

) and you commented my post, let me please reply.
I totally understand your concern.
And I agree with it.
Anyway, technically, the standard apache error pages don't belong to the customer. Many webhosters, if not all, allow their customers to customize their own error pages but if they chose to not do it then the default server's error page are shown.
As described, our script does not interfere with customized error pages. It also improves the default system.
Webhosters may choose to go with an owned license, which will be free from any "forced" advertising or rather go with our free product. We tried anyway to made these adverts discreet and descent (in a next release free users will be able to customize the colors of the adword advert to suit their own design) and, as said (a tos is on its way) we'll engage us to not use the bottom slot to run any competitor's campaign. Which seems to be fair enough for everyone.
Hope this clarifies the purpose of this product and, above all, justifies its use.