Is this a 64-bit system?Anders, thank you for your response. The problem was indeed related to 64-bit Windows, and went away after I had re-read this thread, and figured out that I needed to add SetRegView 64 to the script.
If I may make a suggestion to those who maintain the documentation for the registry plugin - you might want to consider adding some explanations regarding the 32/64-bit modes, as some users (as myself) might be unaware of the SetRegView command, or believe (falsely) that it only affects the built-in NSIS commands (EnumRegValue, etc.)
Again, thank you for your help.