I had the same problem when using CPAN Shell - on ActivePerl 5.10.0.1004.
The above solution worked.

I mean:
Edit C:\Perl\lib\CPAN\Config.pm
- and change the yaml_module entry from: 
  'yaml_module' => q[YAML::XS],

to: 
   'yaml_module' => q[],

In reply to Re^4: Winxp, AS perl 5.10 and cpan error by meorero
in thread Winxp, AS perl 5.10 and cpan error by grizzley

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