Description of problem: The Fedora rawhide core Perl 5.10.0 includes CPANPLUS, and the RPM specfile says it depends on IPC::Run, but IPC::Run isn't included in core Perl anymore, so that makes a core Perl dependency on a non-core package, with no way to provide it.
But it looks like IPC::Run may only be needed by CPANPLUS on Win32 anyway, as removing the dependency solves the install problem and CPANPLUS worked fine in my (limited) tests.
It seems either the IPC::Run dependency of CPANPLUS should be removed from the RPM spec file, or else IPC::Run should be included.
Thank you for report. You are right, IPC::Run isn't needed.
Note: the dependency has been removed in version perl-5.10.0-40.fc10, i.e., in perl-CPANPLUS-0.84-40.fc10.