This error has been driving me nuts. We have a server running Apache and Tomcat, serving multiple different sites. Normally the server runs fine, but sometimes an error happ
Have a look at this site, it describes an issue with mod_jk. I came accross your posting while looking at a very similar issue. Basically the fix is to upgrade to a newer version of mod_jk. I haven't had a chance to implement the change in our server yet, but I'm going to try this tomorrow and see if it helps.
http://securitytracker.com/alerts/2009/Apr/1022001.html