This system is great and we have been using it for e-book downloads. Just recently, and with no explanation, we received an IPN error:
"product config file does not exist (/var/www/vhosts/ourdomain.com/httpdocs/title/download/iBookproducts//config.txt)" whereas "product config file does not exist (/var/www/vhosts/ourdomain.com/httpdocs/title/download/iBookproducts/PRODUCT/config.txt)" does of course exist. And why should this happen on two isolated transactions and not at all on others which go through perfectly (for the same product).

Hi Nick,

that's very weird. Try checkout simulator to see if you can recreate the problem. I suspect that something must have happened in the OS level and it messed up the path.