Odd.
2 things to check..
1.) As jz said, make sure u've got the latest of both parts (2.2.4 and Bo-XLink RC2)
2.) Make sure no firewall is active on your LAN connection.. i dont mean normal firewall as in checking ure connection to the internet - but stuff like the XP firewall being turned on for the internal LAN adapter (wouldnt think its possible - but in certain cases it is)... If you need to open a port for Bo-XLink on your LAN (i dont mean forwarding - but open the port in an internal firewall, it's 34520 UDP) ...
I honestly doubt if either of those 2 are the case .. if not, it could be that you have no contacts in messenger mode?? I'm not sure - i thought i fixed that problem - but maybe...
If none of this works, let me know and we'll break out the www.ethereal.com and take a closer look at where it's fucking up..
Cheers
TD