On my my MacOSX, this textile file looks great : http://gist.github.com/262860, you can see a part here : http://skitch.com/mickeymike/nc5e8/picture-25
I deployed it on my archlinux and now here's the result : http://skitch.com/mickeymike/nc5ef/picture-24
I'm using textile and here's my config file :
I just tried with ruby 1.8.7 (it was ruby 1.9) and it works now
I also ran into this on Ruby 1.9 on Arch; I rolled back to a previous version of Ruby 1.9 (don't recall the details), and it started working again.
I had this problem too with 1.9... I installed the Liquid and Jekyll from source to get it working perfectly on my arch box... ( see http://stefan.artspace44.com/2010/jekyll-installationl) The gems on rubygems.org are out-of-date.
Same problem here. Followed Stefans advice and now it works. Would be nice if this could be fixed, though.
I think this problem has been fixed since 2 years ago when the issue was filed. lib/jekyll/tags/highlight.rb looks fine to me.