I finally figured out what the problem was with Ultraviolet. If you get this error message:

   1  Textpow::ParsingError 
   2  (Parsing error in ^to \w+: wrong number of arguments (2 for 0)):

It is probably due to incompatibilities among some combination of your oniguruma C library, oniguruma, textpow, and ultraviolet gems, rubygems, and ruby the language itself.

Here’s my setup, running in Ubuntu, that works:

   1  jacqui@brighter~ $ ruby -v
   2  ruby 1.8.6 (2007-09-24 patchlevel 111) [x86_64-linux]
   3  jacqui@brighter~ $ gem -v
   4  1.0.1
   5  jacqui@brighter~ $ gem list # snippet
   6  oniguruma (1.1.0)
   7  textpow (0.10.0)
   8  ultraviolet (0.10.1)
   9  jacqui@brighter~ $ onig-config --version
  10  5.9.1

I’ll fix the overflow problem (related to code spilling out behind the sidebar) later.