Crashing

[Ganondwarfy]

Title: Crashing

Version: 3.1.3

OS: Windows 8, 8gb RAM, core i7

Java Version: Version 7 update 10 64x bit

Description of Problem:

tekkit keeps going to the "saving chunks" screen when i have a few rail carts moving along tracks. This is then followed by a white screen which i have to manually close the window. help?

I have update windows graphics drivers, java, and restarted, re-installed, etc.

I am also using BDcraft texture pack which doesn't seem to affect anything since it does the same thing either way.

Error Messages:

none.

Error Log:

[sEVERE] A critical error has occurred.

java.lang.ArrayIndexOutOfBoundsException: 4

at railcraft.common.utility.TileUtilityItem.a(TileUtilityItem.java:61)

at railcraft.common.utility.TileMultiBlock.a(TileMultiBlock.java:250)

at railcraft.common.utility.TileMultiBlock.a(TileMultiBlock.java:254)

at railcraft.common.api.InventoryMapper.a(InventoryMapper.java:46)

at railcraft.common.api.InventoryTools.moveOneItem(InventoryTools.java:375)

at railcraft.common.utility.TileItemLoader.moveItemToCart(TileItemLoader.java:252)

at railcraft.common.utility.TileItemLoader.n_(TileItemLoader.java:203)

at xd.n(World.java:2081)

at net.minecraft.client.Minecraft.k(Minecraft.java:1871)

at net.minecraft.client.Minecraft.x(Minecraft.java:825)

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

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