I am happy to report that industrialcraft-2-client_v1.90 appears to work in Minecraft v 1.2.5 with modloader, modloaderMP, minecraftforge-client-2.0.0.68 with the following mods installed along side it. buildcraft-client-A-core-2.2.15pre , buildcraft-client-B-builders-2.2.15pre , buildcraft-client-B-energy-2.2.15pre , buildcraft-client-B-factory-2.2.15pre , buildcraft-client-B-transport-2.2.15pre , buildcraft-client-C-silicon-2.2.15pre , Railcraft_Client_4.3.0 , WirelessRedstone v1.5 , TooManyItems2012_03_30_1.2.5pre, and Recipe Book.
However I am unhappy to report that when I updated my forge to minecraftforge-client-3.0.0.72 as instructed to do so while setting up MCP62 in the IRC channel for that it kill the industrialcraft-2-client_v1.90 ability to load properly. It comes back in modloader log with the following error at the end of the log file.
Apr 9, 2012 6:31:33 AM ModLoader init
FINER: THROW
java.lang.RuntimeException: IndustrialCraft 2: MinecraftForge Major Version Mismatch, expecting 2.x.x
at forge.MinecraftForge.killMinecraft(MinecraftForge.java:440)
at forge.MinecraftForge.versionDetect(MinecraftForge.java:453)
at mod_IC2.load(mod_IC2.java:92)
at ModLoader.init(ModLoader.java:891)
at ModLoader.addAllRenderers(ModLoader.java:189)
at ahu.<init>(ahu.java:77)
at ahu.<clinit>(ahu.java:8)
at net.minecraft.client.Minecraft.a(Minecraft.java:394)
at net.minecraft.client.Minecraft.run(Minecraft.java:732)
at java.lang.Thread.run(Unknown Source)
I can not think of any means to fix this except to downgrade my version of forge or wait for an update to IC2 to include the 72 forge.
Figured this info might be useful.