Error using tcpipmex: Too many output arguments

I am trying to write a simple script to send data across sockets. My code is below:

test = 'String'; t = tcpip('127.0.0.1', 8000); fopen(t); fprintf(t, test); fclose(t);

I am getting an error with the tcpip line: "Error using tcpipmex. Too many output arguments"

Does anyone know why this error is occurring and how to resolve it? Thank you for your help.