I have come across a crash with buildcraft 6.3.3(and 6.3.1) and the latest rotarycraft for 1.7.10. the pastebin crash report can be found here: http://pastebin.com/Kzkyqu0E This occurs when opening the Rotarycraft machines tab in creative. A similar error occures with nei installed. My uneducated gues s is its how buildcraft renders the tileentity from RC. Im looking for a fix for this otherwise I may have to remove BC for the time being :(

nope this is caused by one of the mods you have installed using an to old BC api

Yes. Might be EnhancedPortals. Anything having buildcraft.api.mj in it really.