<%ARGS> $Path => '' <& /Admin/Elements/Header, Title => 'Error' &> <& /Admin/Elements/ToolTabs, current_tab => 'Admin/Tools/Shredder', current_subtab => 'Admin/Tools/Shredder', Title => 'Error', &>

RTx-Shredder extension needs directory to write dumps there. Please, check that you have <% $Path %> and it's writable for your web server.