i installed forge after installing tekkit via the technic pack launcher and it crashed. i got this error report

 

 

30 mods loaded

Minecraft Forge 3.3.8.152

FML v2.2.78.153

Forge Mod Loader version 2.2.78.153 for Minecraft 1.2.5

mod_MinecraftForge : Loaded (minecraft.jar)

mod_AdditionalPipes : Loaded (AdditionalPipes-2.1.3-MCPC1.2.5-r3.zip)

mod_IC2AdvancedMachines : Loaded (advancedMachines_4.0_bukkit.zip)

mod_WeaponMod : Loaded (BalkonsWeaponMod1.2.5.jar)

mod_BuildCraftTransport : Loaded (buildcraft-2.2.14-mcpc1.2.5-r8.zip)

mod_BuildCraftFactory : Loaded (buildcraft-2.2.14-mcpc1.2.5-r8.zip)

mod_BuildCraftEnergy : Loaded (buildcraft-2.2.14-mcpc1.2.5-r8.zip)

mod_BuildCraftCore : Loaded (buildcraft-2.2.14-mcpc1.2.5-r8.zip)

mod_BuildCraftBuilders : Loaded (buildcraft-2.2.14-mcpc1.2.5-r8.zip)

mod_CCTurtle : Loaded (server)

mod_ComputerCraft : Loaded (server)

mod_EE : Loaded (EE2ServerV1.4.6.5-bukkit-mcpc-1.2.5-r5.zip)

mod_ImmibisCore : Loaded (immibis-core_49.1.1_for_1.2.5-bukkit.jar)

mod_IC2 : Loaded (industrialcraft2-1.97-mcpc1.2.5-r1.zip)

mod_ModularForceFieldSystem : Loaded (mffs_rev5_for_1.2.5-bukkit.zip)

mod_IC2_ChargingBench : Loaded (mod_chargingbench-server-1.95b-mcpc1.2.5-r2.zip)

mod_CompactSolars : Loaded (mod_compactsolars-server-2.3.2.10-bukkit-mcpc-1.2.5.zip)

mod_IC2NuclearControl : Loaded (mod_IC2NuclearControl-1.1.10b-mcpc-r1.zip)

mod_IronChest : Loaded (mod_ironchests-server-3.8.0.40-bukkit-mcpc-1.2.5.zip)

mod_NetherOres : Loaded (mod_NetherOres.jar)

mod_PowerConverters : Loaded (PowerConverters-1.3.4-mcpc78-r1 (1).zip)

mod_Railcraft : Loaded (Railcraft-5.3.3-MCPC-1.2.5-r7.zip)

mod_RedPowerControl : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerLogic : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerLighting : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerWiring : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerCore : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerMachine : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_RedPowerWorld : Loaded (redpower-all-2.0p5b2-mcpc1.2.5-r10.zip)

mod_TubeStuff : Loaded (tubestuff_49.1.1_for_1.2.5-bukkit.jar)

 

 

      Minecraft has crashed!     

      ----------------------     

 

Minecraft has stopped running because it encountered a problem.

 

 

 

 

--- BEGIN ERROR REPORT 5d5626ed --------

Generated 7/30/12 9:11 PM

 

Minecraft: Minecraft 1.2.5

OS: Windows 7 (amd64) version 6.1

Java: 1.7.0_05, Oracle Corporation

VM: Java HotSpot 64-Bit Server VM (mixed mode), Oracle Corporation

LWJGL: 2.4.2

OpenGL: AMD Radeon HD 6310 Graphics version 4.0.10318 Compatibility Profile Context, ATI Technologies Inc.

 

cpw.mods.fml.common.LoaderException: cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: net/minecraft/server/BaseMod

at cpw.mods.fml.common.Loader.load(Loader.java:436)

at cpw.mods.fml.common.Loader.loadMods(Loader.java:592)

at cpw.mods.fml.client.FMLClientHandler.onPreLoad(FMLClientHandler.java:193)

at net.minecraft.client.Minecraft.a(Minecraft.java:383)

at net.minecraft.client.Minecraft.run(Minecraft.java:735)

at java.lang.Thread.run(Unknown Source)

Caused by: cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: net/minecraft/server/BaseMod

at cpw.mods.fml.common.Loader.loadModClass(Loader.java:527)

at cpw.mods.fml.common.Loader.attemptFileLoad(Loader.java:561)

at cpw.mods.fml.common.Loader.load(Loader.java:419)

... 5 more

Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/BaseMod

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(Unknown Source)

at java.security.SecureClassLoader.defineClass(Unknown Source)

at java.net.URLClassLoader.defineClass(Unknown Source)

at java.net.URLClassLoader.access$100(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Unknown Source)

at cpw.mods.fml.common.Loader.loadModClass(Loader.java:494)

... 7 more

Caused by: java.lang.ClassNotFoundException: net.minecraft.server.BaseMod

at java.net.URLClassLoader$1.run(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

... 22 more

--- END ERROR REPORT 6cc3db28 ----------

 

 

 

Tekkit modifies things and as such is incompatible with Forge-proper.  Ask on the tekkit forums, they may be able to help you.

 

For note, it is *very* easy to make your own tekkit-like setup without using tekkit, it is not needed. 

i needed it for a tekkit server i wanted to join

In that case, the tekkit client pack should already have everything you need. 

Yeah. Overmind's right. But tekkit is kind of screwy, and upgrading forge is going to break it.