The easiest way if you installed it in package format would be to do:
pkginfo | grep perl (output should look similar to :)
yadda/yadda/yadda/perl
pkgrm yadda/yadda/yadda/perl
This will wipe out the old and then go to the sun website and download the perl package
then try
pkgadd -d ./perlPackageName
Hope that helps:-)