I hope my advice (use phpMyAdmin or similar as workaround) was helpful.

I do appreciate the information. Unfortunately for me, the extent of my database knowledge consists of creating the database and the user and then adding the user.

I don't know how to edit tables using phpMyAdmin and I'm afraid I might push the wrong button and destroy the forum. I destroyed a Drupal installation once and I'll never forget it! (It is funny now but it wasn't funny at the time.)

Log into phpMyAdmin, open the database where the forums tables are stored. The table *_settings holds ... ahem ... the settings. Push the tab for showing the entries[1]. This table has the structure name, value (two fields in every row). Search for the row where auto_lock_old_threads is the name. Left handed of the field name you should find (from left to right) a checkbox, a field with a pencil and one with a red cross. With the pencil in the row of auto_lock_old_threads you'll open a new page with a form where you can edit the value. Edit the value and press the ok-button, that's it.

[1] Typically it is the first tab, left of tab for structure.

Tschö, Auge