Magister

this error can also be caused by a duplicate item id that was not caught on the server startup, if you find the duplicate item IDs and fix them you will not have to delete your player data. i have had it happen before

hey, i have had this happen on a server, more than once 2012-10-06 18:31:49 [iNFO] [WeaponMod] Properties file read succesfully! java.lang.IllegalArgumentException: Slot 181 is already occupied by cpw.mods.iro nchest.BlockIronChest@72cd429b when adding denoflionsx.items.waxBlock@1d008ff that part of your error log shows what is causing it, you have two or more items that have duplicate block IDs in use to fix it just modify the config files of any new mods to use open ids and the problem should be fixed EDIT: from what i have seen when you get bootted with that error it means that one of the items with a duplicate ID is in your inventory, you can delete your character info off the server to fix it but you loose all your items. or you can have them track down the item(s) causing the issue, i once had it happen with a wooden axe