Since you are using bge(4), I suggest you do following things:
- Add options ETHER_INPUT_CHAIN and options ETHER_INPUT2 in your
kernel config file
- Change line 2119 in netinet/ip_carp.c
  from:
  #define CARP_LOCK_INIT(cif) lockinit(&(cif)->vhif_lock, "carp_if",
0,  LK_NOWAIT);
  to:
  #define CARP_LOCK_INIT(cif) lockinit(&(cif)->vhif_lock, "carp_if", 0,  0);
  i.e. strip the LK_NOWAIT

Hope it will work for you.

Best Regards,
sephe