I get the 4 lines also, the macro reads the first 2.
Also, here's my Device manager port settings (all default):
Communication Device Class ASF example (COM11)
Port settings: 9600, 8, None, 1 None
Advanced: Use FIFO checked, both sliders at max, Com Port Number= COM11
Driver: Atmel Ic., 08/01/2013, 6.0.0.0 etc........
It concerns me that you need to force the baud rate.......which may be related as to the failure of the macro to get the data.
I will try to write a small test excel spreadsheet tomorrow for you that all it does is get the temperature & humidity, no 3458a GPIB.
Ian.