Well, i have my own personal modpack and i'm using mekanism (which works just fine) and a bunch of other mods, but there is 1 problem. Every time i try to add mekanism generators, Minecraft just crashes when i try to start it up. I tried about 5 versions now and all of them crash my game. Does anyone know how to fix this cause i really need mekanism generators in order to work with mekanism itself.

Post the crash log up @ pastebin so it can be reviewed. The problem may be as simple as you trying multiple versions of mekanism, and you leaving a duplicate copy in the mods folder. Make the log available and someone will review it.

No it's not i tried to remove all other mods but now it says there is something with the biogenerator

Caused by: java.lang.NoClassDefFoundError: mekanism/generators/common/tile/TileEntityBioGenerator
at mekanism.generators.client.GeneratorsClientProxy.registerSpecialTileEntities(GeneratorsClientProxy.java:40)
at mekanism.generators.common.MekanismGenerators.init(MekanismGenerators.java:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:513)
at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.initializeMods(Loader.java:691)
... 10 more
Caused by: java.lang.ClassNotFoundException: mekanism.generators.common.tile.TileEntityBioGenerator
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 38 more
Caused by: java.lang.NoClassDefFoundError: mekanism/common/ISustainedData
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 40 more
Caused by: java.lang.ClassNotFoundException: mekanism.common.ISustainedData
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 44 more

Well that's what i get now

did you try re-downloading it? it most likely wont work but its worth a try

yep i tried that several times

I would try downloading the IC2 API, but I can't help you if that doesn't fix it. Try setting up a modding environment with only Mekanism installed?