cpan[1]> install Tk
Going to read '/home/ubuntu/.cpan/Metadata'
  Database was generated on Thu, 12 Jul 2012 01:19:03 GMT
Running install for module 'Tk'
Running make for S/SR/SREZIC/Tk-804.030.tar.gz
Checksum for /home/ubuntu/.cpan/sources/authors/id/S/SR/SREZIC/Tk-804.030.tar.gz ok
Scanning cache /home/ubuntu/.cpan/build for sizes
............................................................................DONE

  CPAN.pm: Going to build S/SR/SREZIC/Tk-804.030.tar.gz

Warning: No success on command[/usr/bin/perl Makefile.PL INSTALLDIRS=site]
'YAML' not installed, will not store persistent state
  SREZIC/Tk-804.030.tar.gz
  /usr/bin/perl Makefile.PL INSTALLDIRS=site -- NOT OK
Running make test
  Make had some problems, won't test
Running make install
  Make had some problems, won't install
Could not read metadata file. Falling back to other methods to determine prerequisites
Failed during this command:
 SREZIC/Tk-804.030.tar.gz                     : writemakefile NO '/usr/bin/perl Makefile.PL INSTALLDIRS=site' returned status -1

cpan[2]>