Hi!
This problem has been discussed in - (Microsoft KB)
http://support.microsoft.com/kb/888228/en-us
I figure out that - You can solve this problem by making some changes in connection string of client. You can also check-out IP address. There may be some error.
Try to ping the client node (PC). If connection is proper, also connect to the node as administrator to client. There are cases where connecting to node may solve this problem automatically.
Some people also suggest that using IP Address instead of server name could solve this problem.