If I try to install DateTime, I get this: lizxp-4:~ lizx$ cpan DateTime CPAN: Storable loaded ok (v2.18) Going to read /Users/lizx/.cpan/Metadata Database was generated on Fri, 06 Jan 2012 20:10:31 GMT CPAN: YAML loaded ok (v0.78) Going to read /Users/lizx/.cpan/build/ ............................................................................DONE Found 35 old builds, restored the state of 35 Running install for module 'DateTime' Running Build for D/DR/DROLSKY/DateTime-0.72.tar.gz Prepending /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/arch /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/lib to PERL5LIB for 'get' Has already been unwrapped into directory /Users/lizx/.cpan/build/DateTime-0.72-LkeH0n Prepending /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/arch /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/lib to PERL5LIB for 'make' Could not make: Unknown error Prepending /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/arch /Users/lizx/.cpan/build/JSON-PP-2.27200-mFYxJ8/blib/lib to PERL5LIB for 'test' Running Build test Can't test without successful make Running Build install Make had returned bad status, install seems impossible ---- I don't know what else to try.