there is actually another bug in the first create statement (I assume it is created with SQLyog GUI):
“create table `logfiles`.`tester` ( `id` int NOT NULL AUTO_INCREMENT UNIQUE , `field1` varchar (250) , PRIMARY KEY ( `id`)) “
UNIQUE keyword should not be there when PRIMARY is! You get a UNIQUE index and a PRIMARY key as well and autoincrement 'is linked' to the UNIQUE KEY this way – not the PK. We know that there are issues with this UNIQUE keyword introduced with beta4! One more here is that 'dublicate …' does not handle autoincrement attribute with a UNIQUE (non-PK) KEY.