@darkhoernchen buidcraft pipes allways give problems. making all pipes invisible and gives errors on the server console: 1: when you open a world in singleplayer and later via server in multiplayer. 2: when using mIDas 3: when using your favorite rollback tool 4: when there is a crash on your server and you get it back up again. (sometimes) 5: when a black cat walks by buildcraft pipes are seroiously bugged this way. last time I had this problem I just went to all locations my server console told there were bugged pipes and fixed it by hand. after that I told everyone to look into redpower tubes and never had this problem again. redpower tubes are much better. this weekend I'm doing the big migration to tekkit lite and only have to change 10 buildcraft pipes by hand. I've looked my ass off for a solution by the way. there is none to be found. If someone really finds a solution please post it here. you're probably the first one with a solution and need a special top of the list sticky post in every buildcraft related forum. edit: @ havocx42: when using worldedit schematics, buildcraft wooden pipes sometimes reverse. but this is really the only problem. maybe those guys know something we all dont.
my input for this thread after converting an extreme world save. (over 1,5, gigs.) change interdiction torches to normal torches or be prepared for huge amounts of stone blocks 129 > 50 and make sure all forcefields are off. I just deleted all forcefield cores in my world to be sure. the active forcefields give me an "immibis.ars.projectors.*********" block error. this is resolved when all forcefields are off before converting.