Followed the instructions

my little forum uses GeSHi as syntax highlighter (example). To enable it you just >>need to set syntax_highlighter to 1 (BB Code has to be enabled, too) in the advanced >>settings (Admin → Settings → Advanced settings).

but the button doesn't show up nor does the [ code ] tag work. Verified that /modules/geshi files exist.

Am I missing something?

Demo site, feel free to take a look:

Username: admin
Password: pass
http://quickforum.tk/forum/demo/

Apache version 2.2.17
PHP version 5.2.17
MySQL version 5.0.92-community
Architecture x86_64
Operating system CentOS