Help with Migration/Foreign Key

[Chris Hoover]

I need some help.  I am under presure from management to migrate and
existing Sybase ASA database to Mysql for a proof of concept.

I have done most of the work, but am having an issue creating a foreign
key.  I keep getting the "Can't create table './mysqk/#sql-d70_1f.frm'
(errno: 150)" error.  I have looked in the documentation, and everything
seems to be fine.  Please advise on what is wrong.

Thanks,

Chris

Here is the offending statement:

ALTER TABLE clinic_consent_form
   ADD CONSTRAINT fk_clinic_c_ref_782_system_t
   FOREIGN KEY (tab_id, class) REFERENCES system_tabs(tab_id, class);


Here are the two tables involved:
CREATE TABLE `system_tabs` (
 `tab_id` bigint(20) unsigned NOT NULL auto_increment,
 `object_name` varchar(32) NOT NULL,
 `description` varchar(64) NOT NULL,
 `class` int(11) NOT NULL,
 `audit_flag` smallint(6) NOT NULL default '0',
 `active_ind` char(1) NOT NULL default 'Y',
 PRIMARY KEY  (`tab_id`,`class`),
 UNIQUE KEY `tab_id` (`tab_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `clinic_consent_form` (
 `clinic_id` bigint(20) NOT NULL,
 `tab_id` bigint(20) NOT NULL,
 `class` int(11) NOT NULL,
 PRIMARY KEY  (`clinic_id`,`tab_id`,`class`),
 KEY `fk_idx` (`tab_id`,`class`),
 CONSTRAINT `fk_clinic_c_ref_473_clinic` FOREIGN KEY (`clinic_id`)
REFERENCES `clinic` (`clinic_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;