Old version help

[spudgunguy]

Ok so I had been playing an older version of Voltz (1.1.2ish I think, it was in Minecraft 1.4.7) that I had made some changes to. I had taken out Fluid Dynamics and added Mystcraft, Buildcraft, and part of Redpower and had a good world going. I wanted to check out the new versions so I made a copy of my modified Voltz folder and updated to the current build. However I stopped playing and let it sit for a few weeks, and when I copied the Voltz folder back into the .technic folder, the game refused to load. Is there any way I can fix this? I really want to keep my old world especially since Voltz is completely different now.

In my mods folder are:

[1.4.6]ReiMinimap_v3.2_06

AssemblyLine_v0.2.8.88

AtomicScience_v0.4.1.162a

BasicComponents_v1.2.6.339

buildcraft-A-3.4.3

ElectricExpansion_v1.4.7

ICBM_Contraption_v1.0.6.168

ICBM_Explosion_v1.0.6.168

ICBM_Sentry_v1.0.6.168

InvTweaks-1.50-1.4.7

MekanismGenerators-v5.4.1

MekanismGenerators-v5.5.4

MekanismTools-v5.4.1

MekanismTools-v5.5.4

Mekanism-v5.4.1

Mekanism-v5.5.4

MFFS_v2.3.0.3

ModularPowersuits-0.3.2-199

mystcraft-uni-1.4.7-0.10.1.00

nei_plugins-1.0.4.5a

Railcraft_1.4.7-6.17.0.0

RedPowerCore-2.0pr6

RedPowerDigital-2.0pr6