How to Create Form Library for Publishing Site in Sharepoint 2010

when i create a site collection without creating the root  in the web application

for example i have my publishing sharepoint site with this url

http://sp2012:33333/sites/MyPublishingSite/

Since this is a publishing site, by default, the InfoPath form service and Form library had been disabled. when i try to create a form library to store all the InfoPath form that I created for this site.

First i need to activate the Site Feature. Click on the Site Setting from the Site Action drop down menu.


then click on the Manage site features in the Site Actions Section.



then click on activate button to enable the Form Library in the publishing site.

After i successfully create the form library, then i want to publish the InfoPath Form to the library that i had created. when i launch the publishing wizard in the InfoPath 2010.



However I always encounter the following Error Messages.

when i use the root of the web application as the location Sharepoint or InfoPath Forms Service site.
then i will get this error. the root cause of this issue is that the root did not create after the web application is instantiate, since I only create a sub site collection under the sites



when i use the sub site to host the InfoPath form, i received "the following URL is not valid" error message. the root cause of this problem is that the InfoPath form can't be host on any sub site that the root site not being created.



after i google the web, the following link really help me figure out the root cause of all the issue.

Publishing Infopath To SharePoint: "the following url is not valid" Error