ikiwiki 3.20110712: A try to rename a page through the web interface without plugin attachment enabled renders:
Error: Undefined subroutine &IkiWiki::Plugin::attachment::attachment_holding_location called at /usr/share/perl5/IkiWiki/Plugin/rename.pm line 326.
Enabling attachment makes it work. Some check if attachment is enabled before running that code path would solve it. Not sure of the best way to check it. --Daniel Andersson