You should check your web.xml file to ensure that the xml elements are in order. (this also goes for all of the deployment xml files).
If you get an error such as the following in deployment:
...The content of element type "<insert_element>" must match
Then the sub-elements should be put in the same order as the error message.
Should deploy now.
I had the same problem. I was running JBoss 3.2.3 (Tomcat 4.x). Upgrading to a later JBoss release (3.2.5) that included Tomcat 5 fixed the problem. See the note on the Jakarta taglibs site (http://jakarta.apache.org/taglibs/doc/standard-doc/intro.html) for the reason why this is so.