After some troubleshooting< I determined the following:
Older Omega2+ (with older firmware) worked as expected. No problems connecting using SSH on PuTTY.
I was able to connect to my new Omega2 using SSH on my older computer which had an older version of Putty.
I uninstalled and removed all Putty files (not as easy as one would hope) then reinstalled and tried again with the same results.
Finally, I noticed that I had the 32-bit version of Putty and installed the 64-bit version instead. That finally worked. So there is something with using the latest 32-bit putty on 64-bit windows that gives this fatal error with the latest version of Omega2+ firmware when doing SSH.
At least it's working now so I can move on to the next step.
So in the main putty connection dialog, select serial instead of ssh and set the serial port you are using, this will depend on your hardware as to which com port you should use. In windows you may be able to look at the removable hardware to see which port the Omega is connected. Remember to set the baud rate to 115200, 8ns. FedLoan Servicing