When I start up my mod pack for 1.12.2 Forge it comes up with the error: The game crashed whilst initializing game Error: java.lang.NoClassDefFoundError: cpw/mods/fml/common/event/FMLInitializationEvent
I've found that for some people it does not work due to the versions of some of the mods not being correct but it seems that this is not the case for me.
Here is the crash report: