1.2.5 is no longer supported on this forum.
Please update to a modern version of Minecraft for support.
edit: i accidentally pressed last page and bumped this
Nope, you're just registering the item twice. Your block calls this method which creates an item to which you then create another item under the same name.
I fixed it, I kept following this line of the crash report- net.minecraftforge.fml.config.ConfigFileTypeHandler$ConfigLoadingException: Failed loading config file usefulbackpacks-server.toml of type SERVER for modid usefulbackpacks
and just kept deleting every server.toml or config file it said up until i deleted the forge.toml and then it worked.