Hi Michael
I am having a similar issue but with the Keysight E5080B ENA.
Details as follows:
VNA Tools version 2.8.8578
ENA firmware version A.15.75.32 (64 bit)
NI Visa version 18.5
GPIB Address 16
HiSLIP Enabled, Address 0
When setting up the VNA Device using Agilent_ENA_Series driver, Test Device gives 'Instrument identification query passed' but VNA gives error message:
[SCPI: -113]: Undefined header; TRIG AVER
Visa Performance Test also passed.
Running any other measurements gives more similar SCPI command errors (undefined header, missing parameter).
Do you know the solution?
Best regards
James