Yes, I did install .NET 3.5.1 and IIS (could not install it without) just after posting the question and it worked. I also had to change the Log On user on both services properties to the admin account is question.
I'm no having another problem when distributing to the external server. The task fails but it still create and empty file (0 KB) on the server with a random name that looks like a hash key of some sort.
Already contacted Qlikview Support and waiting for an answer.
Thanks for the info anyway. It confirmed what I did.