Eugene,
You do not have to add JSTL libraries manually. In the New Web Project wizard, you can select JSTL version in the Project Configuration section.
I could not replicate the issue at my end on JBoss AS 7.1.1. I assume you are working with JBoss AS 7.1.1 and mistakenly mentioned JBoss AS 1.7.1. The JSTL tags are rendered correctly in the output.For JavaEE 7 project, the JSTL version is 1.2.2. While I see no issues with JSTL 1.2.1 added to JavaEE 7 project, please check if you see the same issue with JSTL 1.2.2.
Please elaborate on what exactly you mean when you say it failed. Please share the entire error details with us. Please prepare a sample project which exhibits the issue and send it to help us replicate the issue at our end.