In Minecraft 1.5.1, I get this error when I add in IC2...I've tried multiple forge version, multiple stable IC2 version from the Jenkins. (294,295,290)...I figured that I'd post this here since it only happened when I added IC2. I also did install the API compatibility fix.
That error means there's a .. circle in the chain of dependencies. ie Mod A must run after Mod B, and Mod B must run after Mod A, so it can't figure out what order to load them.
I know the Thermal Expansion release today could trigger that, though they released another version that fixed the potential cycle (but possibly broke some Forestry integration). If you happen to have Thermal Expansion installed, I'd recommend trying to update that ... otherwise, um, dig through the Forge log and hope you find something obvious?
Thanks so much! Updating TE solved that now I have a forestry/thaumic bees problems but I think I need to update that too.