There are no obvious differences in the setup of the various machines. All are SP3.
I am, indeed, able to install when I deselect the context menu function. Unfortunately, this is exactly the functionality I am after. When I run the program after such an install, when I attempt to close the advanced menu (whether or not I try to activate the context menu), I get the following message.
Access violation at address 00555755 in module rightload.exe. Write of address 00000012.
-----Paul-----