Fatal error: Call to undefined function lock_acquire()

Question

I'm using Drupal Version 6.25.

I duplicated an existing drupal page and tried to install it locally on my system.
After the Step where I entered the database information I got this fatal error:

Fatal error: Call to undefined function lock_acquire()

it seems to be located in:

modules/system/system.module on line 810

but unfortunately I couldn't figure out how to fix it.

Hopefully somebody of you know how to fix it because I can't go any further and I need this duplication locally.

Answer 1

At the top of the PHP in system.module add:

include_once './includes/lock.inc';

Then run update.php and clear your cache.