Karl confirmed in the latest thread for RFN that the site he was hosting through went under, and rather than pay for something different, the guys decided to dissolve the podcast.
Too bad, it was a pretty good show.
But he also confirms that he'll be sticking around and doing some guest spots on RFN in the near future, so there's that. Personally I really liked the Karl & Mike duo on RFN, so it's always fun to hear those two again on the show.