Ruby mXML error

From EggeWiki

I received this error on my Mac OSX 10.5

After using Mac Ports to install Ruby, and then installing Ruby gems 1.3.3, I received this error when installing rubyosa.

$ sudo gem install rubyosa
Building native extensions.  This could take a while...
Building native extensions.  This could take a while...
Successfully installed libxml-ruby-1.1.3
Successfully installed rubyosa-0.4.0
2 gems installed
Installing ri documentation for libxml-ruby-1.1.3...
 
Enclosing class/module 'mLibXML' for module XML not known
 
Enclosing class/module 'mXML' for class Attr not known
 
Enclosing class/module 'mXML' for class AttrDecl not known
 
Enclosing class/module 'mXML' for class Attributes not known
 
Enclosing class/module 'mXML' for class Document not known

Attempting a sudo port upgrade all...

Oops.. never do sudo port upgrade all. Rather, I needed to sudo port selfupdate and sudo port upgrade outdated.