Ruby 1.8.6 Source and Apt-Get Upgrade

[subsorama@gmail.com]

Hi,

I am hoping to get some advice with a problem I have gotten myself into;

I upgraded my packages using apt-get yesterday and have found an issue  
with my installed (source built) version of Ruby 1.8.6. I am wondering  
if the update has interfered with my version of ruby as some of my  
rails projects no longer load correctly.

Error:
NoMethodError (undefined method `fdiv' for 0:Fixnum):
    /usr/lib/ruby/1.8/yaml/rubytypes.rb:146:in `is_binary_data?'
    /usr/lib/ruby/1.8/yaml/rubytypes.rb:165:in `to_yaml'
    /usr/lib/ruby/1.8/yaml.rb:391:in `call'
    /usr/lib/ruby/1.8/yaml.rb:391:in `emit'
    /usr/lib/ruby/1.8/yaml.rb:391:in `quick_emit'
    ...

RubyGems Environment is I think still showing the right info:
  - RUBYGEMS VERSION: 0.9.5 (0.9.5)
  - RUBY VERSION: 1.8.6 (2007-09-24 patchlevel 111) [i686-linux]
  - INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: /usr/bin/ruby
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-linux
  - GEM PATHS:
     - /usr/lib/ruby/gems/1.8

dpkg --get-selections shows:
ruby1.8		install
ruby1.8-dev	install


Is it possible apt-get broke something in this situation, and would a  
reinstall of ruby from source as I am now considering be a good idea  
to take at this stage? Unfortunately I need to stick with RubyGems .9  
and Ruby 1.8.6 for now for my current projects - so I can't just  
upgrade to 1.8.7.

Any advice or suggestions greatly appreciated.

Many thanks,

Dominic