Plesk 8.1 and spamassassin

I've just finished putting together a new UK2 Plesk server and found a problem when trying to "spamassassin --lint" after installing Spam Guardian.

Failed to run DNS_FROM_AHBL_RHSBL RBL SpamAssassin test, skipping:
 (Can't call method "bgsend" on an undefined value at
 /usr/lib/perl5/site_perl/5.8.5/Mail/SpamAssassin/Dns.pm line 112.

It would appear as though some required perl libs aren't loaded which can be proven with:

# perl -e "use Net::DNS::Resolver"

So, a quick couple of apt-get installs are required to load the respective libraries:

# apt-get install libnet-ip-perl libnet-dns-perl

I'm not sure why these aren't loaded as dependancies of spamassassin, but adding the libs seems to have fixed the problem. Recheck the "spamassassin --lint" and the errors should have gone.