[djbaxter]

Those are three separate SQL statements:

ALTER TABLE user DROP receivebulletin;

That one failed because you already deleted that table.

Try the following two separately. If you get an error like you did above, basically saying the table doesn't exist, don't worry about it - that's just telling you there's nothing to delete.

ALTER TABLE user DROP INDEX receivebulletin;

ALTER TABLE user DROP receivebulletin_type;

When all of those are removed, then you can reinstall the add-on.