Bob, I understand your problem although you do not explain it well. You get the error all the time (even after you VNC the monitor and click on the appropriate button) and that is OK. But after you turn the screen off, it does it again? Of course, the issue here is with EWF - Disable it and then let the monitor run properly, VNC it, click to the button you want to click and then ENABLE EWF again, and that will be it!
The screen will accept yoru commands, but will ignore all history when it is switched off because EWF is ENABLED (and should stay like that anyhow). You only DISABLE it to configure things and then put it back to ENABLE again.
Can you do this and let me know?
Regards, Bill