The following message appears if you try to modify properties (e.g. the log message) while the propchanges hook is not enabled.

Repository has not been enabled to accept revision propchanges;
ask the administrator to create a pre-revprop-change hook

This hook is nothing else than an executable script located in repos/hooks/ that exits with 0 or 1 if defined conditions are not fulfilled. You can remove the file suffix tmpl from pre-revprop-change.tmpl¹ if the template already exists or you create it from the scratch.

For Unix systems the script looks like

#!/bin/sh
exit 0;

and for Windows it’s

@echo off
exit /B 0