i'm getting this error when starting my server with latest COFHcore, EnderIO, and BigReactors.

http://pastebin.com/XgqVTZjn

apparently COFHcore changed thier API and i was told to inform you of this.

are you using the latest release of big reactors?(0.4.0A)
is ender io and COFH updated?(please go check before you respond)
cofh mods: http://minecraft.curseforge.com/members/TeamCoFH/projects
ender io: http://minecraft.curseforge.com/mc-mods/64578-ender-io/files

Yep, looks like they changed the API in 3.0.0B9. I'll get an update out ASAP.

Strange I have been able to load up the game and a world with out crashing. :/

It only crashes with the newest EnderIO, which looks only for the latest APIs. According to the notes in CoFHLib's docs, this wasn't supposed to be an enforced upgrade until 1.8. Seems like EIO's coders decided to enforce it anyway.

Not very friendly, but handy.

EnderIO-1.7.10-2.2.5.311 with cofh 3.0.0B9 AND you mod(0.4.0A)
I constantly update all mods in my private pack, so I don't understand why I'm not crashing.

Upgrade to 0.4.1A.