ospf netmask mismatch

Hi. I have bird 1.2.2 running on debian lenny on two routers connected by a nonbroadcast configuration. first router has 212.71.191.77/30 on its interface, the second 212.71.191.78/30. They can't negotiate ospf and I get this in the log: bird: OSPF: Bad HELLO packet from 212.71.191.77 - netmask mismatch (255.255.255.128) both routers have additional private prefixes from /25 on their interfaces. Is there a problem with such a setup? it works fine on older birds in the rest of the network. thanks for any pointers mk