importimg Joomla 1.5 database via mySQL dump however it gives error "1071 - Specified key was too lengthy max key length is 1000 bytes"

the culrpit sql statement is:

    CREATE TABLE  `jos_core_acl_aro` (

 `id` INT( 11 ) NOT NULL AUTO_INCREMENT ,

 `section_value` VARCHAR( 240 ) NOT NULL DEFAULT  '0',

 `value` VARCHAR( 240 ) NOT NULL ,

 `order_value` INT( 11 ) NOT NULL DEFAULT  '0',

 `name` VARCHAR( 255 ) NOT NULL ,

 `hidden` INT( 11 ) NOT NULL DEFAULT  '0',

  PRIMARY KEY (  `id` ) ,

  UNIQUE KEY (  `section_value` ,  `value` ) ,

  KEY  `jos_gacl_hidden_aro` (  `hidden` )

  ) ENGINE = MYISAM DEFAULT CHARSET = utf8 AUTO_INCREMENT =11

MySQL stated:

   #1071 - Specified key was too lengthy max key length is 1000 bytes

The origin &lifier destination database is UTF8. I still have no idea why this error happens :(

mysql stores utf8 encoded chars as 3 bytes

your key

UNIQUE KEY (  `section_value` ,  `value` ) ,

includes a size (240 + 240) * 3 bytes, that is greater then 1000 limit