Hello Elias,
Yes, you can directly update the database. If using MySQL, something like the bellow:
update Media set VolStatus="Used" where VolStatus="Error";
If you're going to do this, set the status to "Used" or "Full" and then bacula will recycle the volumes when its retention periods expires.
Nevertheless, I would recommend you to delete these volumes, because they could have entered this error status caused by a label corruption. And If this is the case, when Bacula would try to reuse them, they will enter again into this error status.
Best regards,
Ana