Open JMeter in GUI mode, open your .jmx test plan you have created or create a new test plan, attempt to run the test plan in gui mode. It should prompt you to save before attempting the run, save the .jmx.
Exit the GUI mode.
Open command prompt, navigate to the bin file within the jmeter folder
enter the jmeter -n -t "C:/Username/location of the .jmx file" command
This should run as intended without the error.