Here was described the bug for v1.71, but that bug is still appears in current version. If there is know about this bug, I think you already know, but why you don't fix it? I am confused.
This bug appears on my server, if I exactly follow instruction described in 1.71 bug, and I get same error in server log.
I am using: minecraftforge-3.1.3.99, industrialcraft-2_1.95b, buildcraft-2.2.14, forestry-1.4.4.4_bc2.2, RedPower-2.0pr5b1