How is this a 1.4.2 server is some of the mods aren't even compatible with minecraft 1.4.2 yet
It uses the FTB 1.4.2 modpack. The only major mod that hasnt updated it redpower.
Also, i did some research on my error message, i think that is has something to do with the mods on my side somehow being different from yours. Could you post all the mod config files from the server?