It could be related to a number of different issues. I would suggest to first see if the server is listening for incoming TCP connections on 1433. Open a command prompt and type:
telnet lansync 1433
If you get a blank window, good. If not start troubleshooting protocols, see BOL for more information.
Are you a member of the local administrators group on the lansync server? Is the local administrator group a member of the SA role? Using Vista (see vista prov tool in SP2/BOL).
Good luck 🙂