I got this issue when upgrading:
ALTER TABLE {audio} ADD `remote_size` VARCHAR(255) NOT NULL DEFAULT ''
Failed: ALTER TABLE {audio} ADD `remote_size` MEDIUMINT NOT NULL DEFAULT 0

Update #6001
Failed: ALTER TABLE {audio_image} DROP PRIMARY KEY
Failed: ALTER TABLE {audio_image} ADD PRIMARY KEY (vid, fid)

Have made alterations to DB and seems to be functioning ok.