"Multiple default values" with Rails migration

Rails
1

I am running the following migration with PostgreSQL 8.2.5. It works
fine on my Windows machine, but gives me the below error on Linux
CentOS 4.3. Any ideas? Thanks, Chirag

class CreateUsers < ActiveRecord::Migration
def self.up
create_table :uers do |t|
t.column :timestamp, :timestamp_with_time_zone
t.column :userval, :integer, :limit => 1, :null=> false #will
use smallint becuase of plug-in
end
end

def self.down
drop_table :users
end
end

== CreateUsers: migrating

– create_table(:users)
rake aborted!
RuntimeError: ERROR C42601 Mmultiple default values specified for
column “id” of table “users” Fanalyze.c L1216
RtransformColumnDefinition: CREATE TABLE users (“id” serial primary
key DEFAULT NULL, “user_id” integer DEFAULT NULL, “timestamp” integer
DEFAULT NULL, “userval” smallint NOT NULL)

(See full trace by running task with --trace)