Keysight N1911A Programming Manual page 300

7 MEMory Subsystem
Error Messages
– If either table name is invalid, error –224, "Illegal parameter value" occurs.
– If the first parameter does not match an existing table name, error –256,
– If the second parameter matches an existing table name or save/recall
300
"File name not found" occurs.
register, error –257, "File name error" occurs.
N1911A/1912A P-Series Power Meters Programming Guide