Foreign Key troubles

When I run this script I get the following errors in MySql Query Browser:
Line 11: Can't create table '...users.frm' (errno: 150)                            ErrorNr.: 1005
Line 23: Can't create table '...searches.frm' (errno: 150)                            ErrorNr.: 1005

I've read about MySql's foreign key handling on the web and I can't figure out what my problem is.  Thanks very much for any help.

Here's the script:

CREATE DATABASE IF NOT EXISTS OSearch;

CREATE TABLE IF NOT EXISTS OSearch.Accounts (
 Id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 AcountName VARCHAR(25) NOT NULL,
 Password CHAR(28) NOT NULL,
 Name VARCHAR(100) NOT NULL,
 Email VARCHAR(100) NOT NULL
) TYPE = INNODB;

CREATE TABLE IF NOT EXISTS OSearch.Users (
 Id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 UserName VARCHAR(25) NOT NULL,
 Password CHAR(28) NOT NULL,
 AccountId INT NOT NULL,
 Name VARCHAR(100) NOT NULL,
 Email VARCHAR(100) NOT NULL,

 INDEX (AccountId),
 FOREIGN KEY (AccountId) REFERENCES Accounts(Id)
) TYPE = INNODB;

CREATE TABLE IF NOT EXISTS OSearch.Searches (
 Id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 UserId BIGINT UNSIGNED NOT NULL,
 Query VARCHAR(250) NOT NULL,
 Time DATE NOT NULL,

 INDEX (UserId),
 FOREIGN KEY (UserId) REFERENCES Users(Id)
) TYPE = INNODB;