I just installed a new plugin, but it doesn't work at all.

The best way to install most plugins is using the Plugin Manager. That way you will have the least problems. If you installed a plugin manually (i.e. extracted it into your wiki's plugin folder) or are using an older version of DokuWiki, the following might help.

• Make sure DokuWiki's cache gets purged by touching your conf/local.php.
• Make sure to bypass your browser's cache and force a reload of the relevant page (with Shift-F5, Ctrl-F5, Ctrl-Shift-R or similar).

• Not all plugins are PHP4 compatible, use PHP5 to be on the safe side.
• A few plugins have dependencies (either other plugins need to be installed or some external applications). Check the instructions on the plugin's page if you have installed all required modules.
• Not all plugins work with all DokuWiki versions. Check on the plugin's page if it mentions any compatability information.