Upgrading from 6.x.-1.0-alpha4 to 6.x.-1.0-alpha6 results in database errors

Hi, there.

I just upgraded from 6.x.-1.0-alpha4 to 6.x.-1.0-alpha6 (skipping an alpha version). When I ran update.php, I got these database errors:

* user warning: Can't DROP 'PRIMARY'; check that column/key exists query: ALTER TABLE image_attach DROP PRIMARY KEY in (my includes directory)/database.mysql-common.inc on line 386.
* user warning: Can't DROP 'iid'; check that column/key exists query: ALTER TABLE image_attach DROP INDEX iid in (my includes directory)/database.mysql-common.inc on line 448.
* user warning: Can't DROP 'PRIMARY'; check that column/key exists query: ALTER TABLE image DROP PRIMARY KEY in (my includes directory)/database.mysql-common.inc on line 386.
* user warning: Can't DROP 'image_fid'; check that column/key exists query: ALTER TABLE image DROP INDEX image_fid in (my includes directory)/database.mysql-common.inc on line 448.

These were listed as "failed" in the log:

ALTER TABLE {image_attach} DROP PRIMARY KEY
ALTER TABLE {image_attach} DROP INDEX iid
ALTER TABLE {image} DROP PRIMARY KEY
ALTER TABLE {image} DROP INDEX image_fid

Also, should this happen?

UPDATE {permission} SET perm = 'view advanced help index, view advanced help popup, view advanced help topic, access news feeds, create audio, download audio, edit own audio, play audio, view download stats, attach any existing audio file, create blog entries, delete own blog entries, edit own blog entries, access printer-friendly version, add content to books, administer book outlines, create new books, access comments, post comments, post comments without approval, access site-wide contact form, view date repeats, use date tools, create filenode, download any filenode, edit own filenode, create forum topics, delete own forum topics, edit own forum topics, create images, edit own images, view original images, administer image galleries, import images, access advanced options, access img_assist, use original size, download original image, access content, create book content, create embedded_video content, create live_event content, create page content, create private_blog content, create private_page content, create release content, create release_track content, create simplenews content, create story content, create venue content, delete own book content, delete own embedded_video content, delete own live_event content, delete own page content, delete own private_blog content, delete own private_page content, delete own release content, delete own release_track content, delete own simplenews content, delete own story content, delete own venue content, edit own book content, edit own embedded_video content, edit own live_event content, edit own page content, edit own private_blog content, edit own private_page content, edit own release content, edit own release_track content, edit own simplenews content, edit own story content, edit own venue content, view revisions, create url aliases, access print, search content, use advanced search, send newsletter, subscribe to newsletters, select different theme, administer taxonomy, translate content, upload files, view uploaded files, access user profiles, change own username, access all views' WHERE rid = 3

The "perm" table was set for rows 3 and 4, in Update #6100 and Update #6103 for image_gallery.