i solved the problem, Infopath form services is an enterprise feature....even sharepoint let you "activate" the feature. if you dont have a the enterprise version of sharepoint you will face this problem....
If you have a sharepoint enterprise CAL key you can upgrade your installation and then everything will work. see this link , make sure you dont have any problem with the timer service when you do this.
This is the list of some of the Enterprise services of SP:
Excel Services
Access Services
InfoPath Form Services
Visio Services and more...
I Hope this help you....
I have to admit that was my mistake to try to activate and use a enterprise feature in a standard installation, but sharepoint should have given a more meaningful message ... when trying to activate or when i click in the links.
let me know if this work for you.
ps: sorry for my english