This turned out to be permissions issue. I had to take ownership of the
applicable Registry keys as an Administrator. I was then able to set the
button assignments as an Administrator.
I got an email response from Epson regarding this problem and their only
suggestion was to reinstall the driver, which I had already done.
"Rich Bell" <rg_bell@xxxxxx> wrote in message
>I am trying to set the default programs for my Epson V200 scanner buttons
>using the Scanners and Cameras Control panel applet. When I choose the
>program and click OK I get the following error message:
> Event registration failed: The attempt to change the registered event
> handler failed. Please make sure the device is turned on and connected
> When I press any of the buttons it brings up a dialog that allows me to
> choose a program. The scanner functions normally once the application is
> Any ideas why it won't let me change the registered event handlers?