>> You can't, right now. If you have pdftex and is running Textile, then
>> they're forced on there. That is unless you just remove the links from
>> app/views/wiki/page.rhtml.
>
> It would be nice if instiki detected whether or not those features
> were even available on the system it is running on and then removed
> them if they don't work.  They don't work, for example, on my system.

Instiki does actually detect whether pdflatex is available on the 
system and removes the links if it is not. I'm not quite sure how 
Instiki could test if the latex installation is broken, though.
--
David Heinemeier Hansson,
http://www.instiki.org/      -- A No-Step-Three Wiki in Ruby
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http://www.loudthinking.com/ -- Broadcasting Brain
http://www.nextangle.com/    -- Development & Consulting Services