When updating from 1.8.5+ (Build: 20080702) (2007081000) to 1.9.1+ (Build: 20080702) (2007101514)...

(mysql): ALTER TABLE mdl_groups MODIFY COLUMN password VARCHAR (50) NULL DEFAULT NULL after description

1054: Unknown column 'password' in 'mdl_groups'

There are 4 warnings with this error and at the bottom of the screen, you can select CONTINUE, but nothing ever happens. The same warning page is displayed. If I exit the screen and go back into Moodle, it lets me in and asks me to upgrade files again. The same thing displays and never goes further.