I was having issues with the: Unable to load configuration - bean - blah blah struts-default.xml and the suggestion above to add the "commons-fileupload-1.2.1.jar" fixed it. So the set of jars I now have in my WEB-INF/lib directory is:
commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
commons-logging-1.0.4.jar
freemarker-2.3.15.jar
ognl-2.7.3.jar
struts2-core-2.1.8.1.jar
xwork-core-2.1.6.jar
And

that at least got my war successfully deployed (I'm using gaucho resin because that is what my web provider uses). I will be delving into using Tiles with struts 2 and if I succeed I'll post some helpful tips. It is only by helpful tips that I have gotten this far. Thanks.