I have he same problem on my server. We updated Tekkit from 0.5.2 to 0.5.7 and now when i relog (or a chunk gets reloaded) all the machineblocks are rotated on the side.
Does someone have a fix for this? I've searched on google on this topic and there was a simular problem in august 2012. It was a conflict between the IC2 mod and the multiworld plugin or something... Maybe this can help to fix the problem?
(Source: http://forums.technicpack.net/threads/3-0-3-3-0-4-machine-block-orientation-in-tekkit-3-0-3.11086/page-2)
Thanks!