When VaultWiki is disabled on your site, there is no editor toolbar even when making regular posts. So it seems like there is another issue on your site, and it is not related to VaultWiki. The toolbar is not there on do=edit because VaultWiki is loading the same editor that is already not working on your forum.
VaultWiki throws an error in the Javascript console. This is because VaultWiki can't find the toolbar, which vBulletin has already claimed would be enabled.