services just marked with "-" on some monitored hosts

Hey,

I installed a new hobbit-system to monitor some hosts.
Most hosts and its services are monitored fine, but for 2 hosts all services are marked with a "-" for days now.
I sniffed the traffic with tcpdump and all tests for these hosts are running (e.g. ssh, http) - even in /var/lib/hobbit/rrd there are directories named as the hostnames I specified in bb-hosts.
But for these 2 hosts I just get "-" for all services; no smilies :/

Any ideas? What might i do wrong?

Thanks a lot

mirko