update problem from alpha4 to alpha6 (update 6100)

Hi to all!

I have an update problem from Image alpha4 to last alpha6 version.

This is the log file at the end of update process:

user warning: Can't DROP 'PRIMARY'; check that column/key exists query: ALTER TABLE drupal_image_attach DROP PRIMARY KEY in /var/www/drupal/includes/database.mysql-common.inc on line 386.
user warning: Can't DROP 'iid'; check that column/key exists query: ALTER TABLE drupal_image_attach DROP INDEX iid in /var/www/drupal/includes/database.mysql-common.inc on line 448.
user warning: Unknown column 'blocks.module' in 'where clause' query: DELETE FROM drupal_blocks WHERE blocks.module = 'image_attach' AND blocks.delta = 0 in /var/www/drupal/modules/image/contrib/image_attach/image_attach.install on line 123.
user warning: Can't DROP 'PRIMARY'; check that column/key exists query: ALTER TABLE drupal_image DROP PRIMARY KEY in /var/www/drupal/includes/database.mysql-common.inc on line 386.
user warning: Can't DROP 'image_fid'; check that column/key exists query: ALTER TABLE drupal_image DROP INDEX image_fid in /var/www/drupal/includes/database.mysql-common.inc on line 448.

The following queries were executed
image_attach module
Update #6100
ALTER TABLE {image_attach} CHANGE nid `nid` INT unsigned NOT NULL DEFAULT 0
ALTER TABLE {image_attach} CHANGE iid `iid` INT unsigned NOT NULL DEFAULT 0
Failed: ALTER TABLE {image_attach} DROP PRIMARY KEY
ALTER TABLE {image_attach} ADD PRIMARY KEY (nid)
Failed: ALTER TABLE {image_attach} DROP INDEX iid
ALTER TABLE {image_attach} ADD INDEX iid (iid)
Update #6101
Failed: DELETE FROM {blocks} WHERE blocks.module = 'image_attach' AND blocks.delta = 0

Thanks!