I'm running tomcat 8-RC10 and (attempting) geoserver 2.4.3 deployed from .war. Geoserver won't start with the above error, and the catalina.out (which is so long and detailed as to be almost useless) seems to have trouble at the point:
ERROR [context.ContextLoader] - context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'geoServerLoader' defined in URL [jar:file:/home/XXX/tomcat/webapps/geoserver/WEB-INF/lib/main-2.2.4.jar!/applicationContext.xml]: Cannot resolve reference to bean 'resourceLoader' while setting constructor argument;
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'resourceLoader' defined in URL [jar:file:/home/XXX/tomcat/webapps/geoserver/WEB-INF/lib/main-2.2.4.jar!/applicationContext.xml]: initialization of bean failed;
nested exception is java.lang.IllegalArgumentException: The resource path [WEB-INF] is not valid.
Appreciate any suggestions, I'm quite clearly in over my head here.
If anyone else runs into this, it seems that tomcat 8 is not supported by geoserver as yet. My recommendation is downloading and unzipping tomcat7 from the .tar, according the instructions at : http://diegobenna.blogspot.com.au/2011/01/install-tomcat-7-in-ubuntu-1010.html