RBL tests don't seem to work

[Jesse Houwing]

DNS resolving works, but somehow I can't seem to get the RBL lists to 
work, or I'm not seeing them (?).
I'm using Spamassassin 2.63 with these settings in the local.cf:

skip_rbl_checks 0
dns_available yes
check_mx_attempts 5
check_mx_delay 5
use_dcc 0
use_razor2 0
use_pyzor 0
score RAZOR2_CHECK 0
The lines from the spamassassin -D -t concerning RBLs are:
debug: DNS MX records found: 0
debug: DNS A records found: 1
debug: RBL: success for 0 of 0 queries
DNS is working judging from these lines, but this is the only ip that is 
being resolved.:

debug: dns_available set to yes in config file, skipping test
debug: is Net::DNS::Resolver available? yes
debug: looking up PTR record for '130.89.1.29'
debug: PTR for '130.89.1.29': 'ictlx034.civ.utwente.nl'
Any pointers as to how to get these active would be appreciated.
Jesse