I've been having multiple issues attempting to install/reinstall forge along with a few other mods just to try out a different MC experience.

Initially I started with a new 1.4.2 .jar, installed forge first, then optifine (testing those two first with magic launcher and seeing no issue in text until I loaded a new world and immediately fell through it).

Loading it through the regular launcher though it seemed to work fine.

I then added Too Many items and then Rei's Minimap, still not experiencing issues.

After adding millenaire (the whole reason for installing forge in the first place) I'm unable to play for more than a few moments after loading a new world (up to about 7 minutes) before MC freezes and crashes.

I uninstalled and reinstalled numerous configurations and can't figure out what the issue is.

I'll be the first to admit I'm not the most tech savvy person but, after exhausting the search bar and wiki I can only find similar instances none relevant enough to solve the issue. Any help at all would be appreciated.

 

 

  BEGIN ERROR REPORT b8cca25b --------

Generated 10/31/12 3:53 AM

 

- Minecraft Version: 1.4.2

- Operating System: Windows 7 (amd64) version 6.1

- Java Version: 1.7.0_04, Oracle Corporation

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

- Memory: 115249592 bytes (109 MB) / 522452992 bytes (498 MB) up to 954466304 bytes (910 MB)

- JVM Flags: 2 total; -Xms512m -Xmx1024m

- AABB Pool Size: 6722 (376432 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used

- FML: MCP v7.19 FML v4.2.6.422 Minecraft Forge 6.0.1.341 Optifine OptiFine_1.4.2_HD_U_B2 6 mods loaded, 6 mods active

mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

FML [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

Forge [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

mod_ReiMinimap [mod_ReiMinimap] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

mod_TooManyItems [mod_TooManyItems] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

Millenaire [Millénaire] (millenaire3.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available

- Is Modded: Definitely; 'forge,fml'

- Profiler Position: N/A (disabled)

- Vec3 Pool Size: 979 (54824 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used

- Player Count: 1 / 8; [ih['ME'/335, l='New World', x=174.32, y=73.00, z=288.55]]

- World New World Entities: 0 total; []

- World New World Players: 0 total; []

- World New World Chunk Stats: ServerChunkCache: 0 Drop: 0

- Type: Integrated Server

 

java.util.ConcurrentModificationException

at java.util.ArrayList$Itr.checkForComodification(Unknown Source)

at java.util.ArrayList$Itr.next(Unknown Source)

at ib.b(PlayerManager.java:71)

at ie.b(WorldServer.java:136)

at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:648)

at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:585)

at bcb.q(IntegratedServer.java:110)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:492)

at fp.run(SourceFile:818)

--- END ERROR REPORT fe018c2d ----------

 

 

Seems like Millinaire has a bug, go talk to them about it.