This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
It probably means that an iterate tag is not defined in the tld file. Out of band comment: if you are going to invest mindshare in general purpose tags, I'd focus on the JSTL (JSP Standard Tag Library) rather than a 3rd party library.