Thanks for reporting.
Below patch should fix the issue, which has been committed as change 12429:
==== //depot/cpanplus/devel/bin/cpan2dist#26 - /Users/kane/sources/p4/cpanplus/devel/
bin/cpan2dist ====
6a7
Show quoted text> use File::Spec;
213a215,217
Show quoted text> ### make sure we use an absolute path, so chdirs() dont
> ### mess things up
> $name = File::Spec->rel2abs( $name );