greg myst pam crash

net.minecraft.util.ReportedException: Exception generating new chunk
at net.minecraft.world.World.func_147439_a(World.java:352)
at gregtech.common.blocks.GT_TileEntity_Ores.setOreBlock(GT_TileEntity_Ores.java:101)
at gregtech.common.GT_Worldgen_GT_Ore_Layer.executeWorldgen(GT_Worldgen_GT_Ore_Layer.java:47)
at gregtech.common.GT_Worldgenerator.generate(GT_Worldgenerator.java:50)
at cpw.mods.fml.common.registry.GameRegistry.generateWorld(GameRegistry.java:106)
at net.minecraft.world.gen.ChunkProviderServer.func_73153_a(ChunkProviderServer.java:220)
at net.minecraft.world.chunk.Chunk.func_76624_a(Chunk.java:1036)
at net.minecraft.world.gen.ChunkProviderServer.func_73158_c(ChunkProviderServer.java:130)
at net.minecraft.world.gen.ChunkProviderServer.func_73154_d(ChunkProviderServer.java:139)
at net.minecraft.world.World.func_72964_e(World.java:417)
at net.minecraft.world.World.func_147439_a(World.java:343)
at com.pam.harvestcraft.WorldGenPamFruitPalmTree.func_76484_a(WorldGenPamFruitPalmTree.java:62)
at com.pam.harvestcraft.PamTreeGenerator.generateSurface(PamTreeGenerator.java:148)
at com.pam.harvestcraft.PamTreeGenerator.generate(PamTreeGenerator.java:21)
at cpw.mods.fml.common.registry.GameRegistry.generateWorld(GameRegistry.java:106)
at net.minecraft.world.gen.ChunkProviderServer.func_73153_a(ChunkProviderServer.java:220)
at net.minecraft.world.chunk.Chunk.func_76624_a(Chunk.java:1031)
at net.minecraft.world.gen.ChunkProviderServer.func_73158_c(ChunkProviderServer.java:130)
at net.minecraft.world.gen.ChunkProviderServer.func_73154_d(ChunkProviderServer.java:139)
at net.minecraft.world.World.func_72964_e(World.java:417)
at net.minecraft.world.World.func_147439_a(World.java:343)
at com.pam.harvestcraft.WorldGenPamFruitTree.func_76484_a(WorldGenPamFruitTree.java:60)