I just installed forge ...1002  with no mod fut Forge alone and i can load any map, it starts then i'm back to the Minecratf main menu.

If i start a new map i get a crash with a null pointer :

 

---- Minecraft Crash Report ----
// My bad.

Time: 17.01.14 18:29
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at cpw.mods.fml.client.FMLClientHandler.setPlayClient(FMLClientHandler.java:699)
at net.minecraft.client.network.NetHandlerPlayClient.<init>(NetHandlerPlayClient.java:221)
at net.minecraft.client.network.NetHandlerLoginClient.func_147232_a(NetHandlerLoginClient.java:110)
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:187)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:2056)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:952)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:869)
at net.minecraft.client.main.Main.main(SourceFile: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 net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
Minecraft Version: 1.7.2
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_40, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 1182531192 bytes (1127 MB) / 1499987968 bytes (1430 MB) up to 2863661056 bytes (2731 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx3G
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
FML: MCP v9.01-pre FML v7.2.69.1002 Minecraft Forge 10.12.0.1002 4 mods loaded, 4 mods active
mcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
FML{7.2.69.1002} [Forge Mod Loader] (forge-1.7.2-10.12.0.1002.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Forge{10.12.0.1002} [Minecraft Forge] (forge-1.7.2-10.12.0.1002.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
JFVMod{1.0} [JFVMod] (JFVMod-1.7.2-1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Launched Version: 1.7.2-Forge10.12.0.1002
LWJGL: 2.9.0
OpenGL: AMD Radeon HD 7900 Series GL version 4.2.12217 Compatibility Profile Context 12.104.0.0, ATI Technologies Inc.
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: [JFVRealism]
Current Language: Français (France)
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null
Anisotropic Filtering: On (16)

Same for me, also the error "java.lang.NullPointerException" comes up when I try to join a multiplayer server.

 

Version 10.12.0.1001 works fine, but 10.12.0.1002 doesn't, it fails to start Single Player or Multiplayer.

Yes, this commit : https://github.com/MinecraftForge/FML/commit/9c96ca4402e4c231285f170281dd543bfffa191a seems to have broken something. Use 1001 until the problem is fixed.