I stumbled on the inconsistency ilg1976 found in the last post as well. Plus, there are a few others in the current CSV file that seem to have gotten in there recently, namely "0" entries in a network's country column. As countries are numbered starting with 1, and -1 for non-countries, that's an error my Postgres complains about when I try to import the data.
For now, I just hacked my import script to replace zeroes by -1 (the first error is the double US/CA entry):
Incompatible entry 226 != 38
Fixed country 0 -> -1 for net 24.170.0.0
Fixed country 0 -> -1 for net 61.0.203.0
Fixed country 0 -> -1 for net 68.124.0.0
Fixed country 0 -> -1 for net 73.99.6.0
Fixed country 0 -> -1 for net 82.0.95.0
Fixed country 0 -> -1 for net 82.0.221.0
Fixed country 0 -> -1 for net 172.186.0.0