This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
After doing some testing, what's weird is that apparently it was the return type of Boolean (rather than boolean) in conjunction with the is/get prefix for the accessor method that was tripping you up.
The following formats work as one would expect:
generates the "Unable to find a value" error (at least under Tomcat -- Resin 3 returns a blank rather than throwing an error).
I'm not as familiar with the JavaBeans Specification as I am with the Servlets, JSP and JSTL specs, so I'm not sure exactly what precept the latter form violates.