If you cannot modify a revision description in Subversion (SVN) because of the following error:
Repository has not been enabled to accept revision propchanges;
ask the administrator to create a pre-revprop-change hook
(or 'almost in Polish' ;)
Repozytorium nie ma włączone możliwości zmieniania atrybutów;
poproś administratora o utworzenie skryptu hook pre-revprop-change
it can be solved by creating an pre-revprop-change.bat file (in case you are using Windows) in the hooks directory of the repository. Of course the file does not have to be empty, it can do something like logging information about changes being made (because Subversion's revision properties are not versioned).
UPDATE:
On Windows 2003 BAT files cannot be empty - see here.