If you accidentally define a biome twice under CustomBiomes in WorldConfig.ini, an incorrect crash message is produced.

e.g if Ocean Island is designated id 75 and 614, the following crash report is generated
net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from Open Terrain Generator (openterraingenerator) Caused by: java.lang.RuntimeException: Could not allocate the requested id 614 for biome Ocean Island. All available id's under 256 have been allocated
even though all id's under 256 have not been allocated. Which could be misleading for new pack makers n stuff.

Thanks,
snarp

Hey @Virtualistik, thanks for the feedback! This is fixed with v7 dynamic biome id's, which retires custombiomes (it only still exists to support legacy worlds).