seems like it happens when your client is trying to obtain the res files from the server. wonder if the res server is in trouble again...
first, try clearing java cache. its one thing ppl always forget to do after reinstalling java.
http://www.java.com/en/download/help/plugin_cache.xml
sometimes re-installing java messes it up and somehow end up with corrupt files. if its the only change you have done and clearing cache doesnt work, try re-clean-installing java too.
and if it doesnt work, try this (with ender)
viewtopic.php?f=27&t=30126
it has all the files you need so that your client does not need to try to access to the server and can skip the process to avoid crashing.