901: You are not attached to the specified server.
Source: FLAG.EXE, PURGE.EXE, RIGHTS.EXE
Possible Cause: The user tried to execute a command on a server other than the default server to which the user was not attached.
Action: Specify a path to the utility on the appropriate server.
Action: Attach to the desired server, and then map a drive to the server and use the new drive mapping in the command. Use the /NS option to attach; otherwise, you will lose the default option.