Check out Solaris Freeware. You can get a binary install of gcc-2.95.3-sol7-sparc-local.gz from there, install it using gunzip, pkgadd, and then hopefully, compile Perl with gcc (you might also want to get gmake and gtar). Currently they only have a binary install for Perl 5.80 for SPARC/Solaris 2.7, otherwise I'd suggest it. Not that anything's wrong with it, but you asked about version 5.6.1.
in reply to Installing Perl on Unix
I'd concur with Abigail-II that Sun's C compiler isn't too hot--gcc has been less problematic for our systems.
Update: make sure you download the correct Solaris version.