Problem when deleting files from the server

Hi all:

	I don´t know if this is a configuration problem or a bug.

	The NFS server works fine but when i add files directly in the
server sometimes the directory does not change in the client directory.

	Here is one example of that:

		From the server:
			I delete all the files.
		Fron the client:
			I make "ls" and all the directory is empty.
		From the server:
			I add some files
		From the client:
			I make "ls" and the directory continues empty and i
only can see the files if i umount and remount the directory.

	I also occurs sometimes if i add a file directly from the server.

	What i am doing bad?

	Can somebody help me?

	Thanks in advance.