There is an ongoing outage on the primary CPAN mirror. It is possible to work around the issue by using MetaCPAN as a mirror.

JROCKWAY / Sub-AliasedUnderscore-0.02 / Changes 
0.02 29 March 2008
     - patch from nothingmuch++ to remove Data::Alias dependency

0.01 Some time in the past
     - initial release