Launcher crashes when logging into my server on new tekkit classic

[spiderwalker]

Launcher Version: 1.2.5

Operating System: windows 7

Java Version: 7 update 7

Antivirus Program: avast

Description of Problem:

was working fine and then suddenly not without any changes to system.

Launcher will show logging in, downloading terrain and then just go to a white screen

Error Messages:

2013-09-01 11:05:56 [sEVERE] A critical error has occurred.

java.lang.IndexOutOfBoundsException

at eloraam.core.ItemParts.b(ItemParts.java:32)

at yr.g(Item.java:244)

at aan.b(SourceFile:84)

at tw.a(RenderItem.java:278)

at aiy.a(GuiIngame.java:756)

at aiy.a(GuiIngame.java:333)

at lr.b(EntityRenderer.java:1087)

at net.minecraft.client.Minecraft.x(Minecraft.java:876)

at net.minecraft.client.Minecraft.run(Minecraft.java:753)

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

2013-09-01 11:05:56 [sEVERE] 41 mods loaded

Optifine OptiFine_1.2.5_HD_S_C6

Minecraft Forge 3.3.8.164

FML v2.2.106.176

Error Log: