plperl.so no such file or directory

I'm migrating our database from CentOS release 5 (Final) to Red Hat
Enterprise Linux Server release 6.1 (Santiago)

I've copied over the database file system and restarted the database
on the new server using the fresh postgresql install and this all
works fine

However if I use one of my plperl functions I get the error.

ERROR: could not load library
"/net/nas20/bin/postgresql_8.4.2/lib/plperl.so": libperl.so: cannot
open shared object file: No such file or directory

I can see /net/nas20/bin/postgresql_8.4.2/lib/plperl.so is present

the limited googling I've done seems to indicate that I need to mess
round with /etc/ld.so.conf
as root. As I don't have root access on either machine is there
another option I can look at?

--
Michael