Alle Thursday 18 September 2008, Tom Cloyd ha scritto:
> I've a fresh compile of ruby 1.8.6

This is the issue. The ruby you compiled is in a different location than the 
one installed by the package manager. I don't use Kubntu, but I guess the one 
installed using the package manager is in /usr, while the one you installed 
manually is in /usr/local (that is the predefined path where the configure 
script wants to install it, of course you can have changed it). When you 
install rubygems using the package manager, the files are put somewhere in the 
/usr/lib/ruby/ directory. The ruby you installed manually (which, I guess, 
comes before the other in your PATH) expects to find its libraries in 
/usr/local/lib/ruby, but rubygems hasn't been installed there.

I can think of two ways you can take:
1) manually install rubygems using your custom install of ruby. This should be 
quite easy to do. This is the easiest and cleanest option.
2) remove the ruby you installed manually, then reinstall it passing the --
prefix=/usr option to configure. This will overwrite the version of ruby 
installed by the package manager, but allow you to use gems and other ruby 
libraries installed with it. This is a very messy solution, and you shouldn't 
use it unless you have a reason not to use option 1.

I hope this helps

Stefano