Console Error

Hello,
I am currently running a server and lately whenever I check the console I get this error over and over again.

11.04 14:56:03 [Server] WARNING No compatible nms block class found.
11.04 14:56:03 [Server] WARNING No compatible nms block class found.
11.04 14:55:38 [Server] WARNING No compatible nms block class found.
11.04 14:55:27 [Server] WARNING No compatible nms block class found.
11.04 14:55:26 [Server] WARNING No compatible nms block class found.
11.04 14:55:26 [Server] WARNING No compatible nms block class found.
11.04 14:55:20 [Server] WARNING No compatible nms block class found.
11.04 14:55:20 [Server] WARNING No compatible nms block class found.
11.04 14:55:18 [Server] WARNING No compatible nms block class found.
11.04 14:55:18 [Server] WARNING No compatible nms block class found.
11.04 14:54:45 [Server] WARNING No compatible nms block class found.
11.04 14:54:44 [Server] WARNING No compatible nms block class found.
11.04 14:54:41 [Server] WARNING No compatible nms block class found.
11.04 14:54:40 [Server] WARNING No compatible nms block class found.
11.04 14:54:38 [Server] WARNING No compatible nms block class found.
11.04 14:54:38 [Server] WARNING No compatible nms block class found.


I it seems that this is popping up more and more. If anyone has had this error before and has figured it out letting me know will be appreciated.

Also this does not seem to be effecting the server in any way, but having this happen multiple times a second must increase lag and server resource usage.