DHCP and failover issues

Hello,

I am trying to implement failover in our dhcp but I don't get it right....
I have 2 SLES/OES servers both can be used as DHCP server without failover (one active, the other not).
server 1 => SLES11SP1 with OES11 (dhcp version is 3.1.3 ESV)
server 2 => SLES11SP2 with OES11SP1 (dhcp version is 4.2.4-P2)

I have defined my failover dhcp services following TID 7004294, so I have defined to services (ip_serv1 and ip_serv2), each failover service does contain:
a) failover object ( FO2SERV2, FO2SERV1), where
Primary server is 10.7.0.248 10.7.0.248
Primary port is 647 847
Secondary server is 10.7.0.250 10.7.0.250
Secondary port is 847 647
Failover split is 128 128
Max. Client Lead Time 3600 3600

b) subnet 10.11.0.0 10.11.0.0 where these subnets have following pool
c) pool pool_10_11 pool_10_11 and these have the following failover attached to
FO2SERV2 FO2SERV1

I think that these parameter follow precisly the TID 7004294, but when I start the dhcpd services on the primary server I get the following messages:

I move from recover to startup
I move from startup to recover
DHCPDISCOVER from 00:23:24:07:84:53 (REFERENCE) via XXX.XXX.XXX.XXX: not responding (recovering)

and indeed I do not get any lease.

What am I doing wrong????
Any suggestions?
Thanks in advance