The only thing logged by the router was this:
0|DHCPC :Retry
1|DHCPC :Retry
2|DHCPC
iscovery
3|DHCPC
iscovery Error
4|DHCPC :Retry
5|DHCPC :Retry
6|DHCPC :Retry
7|DHCPC :Retry
8|DHCPC :Retry
over and over - until i changed the MAC address of the router, then it changed to
0|DHCPC
iscovery OK
1|DHCPC :Retry
2|DHCPC
iscovery
and everything was fine.