When finishing installing tomcat7 on Ubuntu 12.04.
Some example pages throw error (written in Title).
There is JSTL(I don’t know what it is exactly.)
I guess it’s not a big problem, so I googled, and decided ignoring error!!
However, if you’re interested in that error.
There is a great post in here. –> http://administratosphere.wordpress.com/2010/06/23/tomcat-missing-java-standard-tag-libraries-jstl-in-debian-and-ubuntu/