When OpenAjax hub is enabled using the web.xml configuration parameter com.icesoft.faces.openAjaxHub = True, the browser fails to load openajax.js with HTTP 404 error as shown in the attached screenshot of the firebug console. On further investigation found that the path for src attribute for script tag being generated by icefaces differs in case of other js files such as icefaces-d2d.js and openajax.js

For other files the path includes application startup time as shown below -
/xmlhttp/1292322511113/icefaces-d2d.js
/xmlhttp/1292322511113/ice-extras.js

But, the path for openajax.js doesn't include this -
/xmlhttp/openajax.js

The code in question is line 499 in com.icesoft.faces.context.DOMResponseWriter class -

private void appendContentReferences(Element container) {
//load libraries
Collection libs = new ArrayList();
if (configuration.getAttributeAsBoolean("openAjaxHub", false)) {
libs.add("/xmlhttp/openajax.js");
}
libs.add("/xmlhttp" + StartupTime.getStartupInc() + "icefaces-d2d.js");
//todo: refactor how external libraries are loaded into the bridge; always include extra libraries for now
libs.add("/xmlhttp" + StartupTime.getStartupInc() + "ice-extras.js");

It's a trivial fix as demonstrated below -

Remove Line -> libs.add("/xmlhttp/openajax.js");
Replace With -> libs.add("/xmlhttp" + StartupTime.getStartupInc() + "openajax.js");