One thing you may want to try: right-click the MMIP file. Go to Properties. At the bottom of the Properties window (under the General tab) there should be a button that says "unblock". Click that.

It may not help, but give it a shot anyway.

Also, you may have an overzealous antivirus/security program somewhere. Maybe try installing it in Safe Mode.

close media monkey
right click shortcut, Run As Administrator
while MM is running, double click the .mmip
it will install no problemo. You only need to "run as administrator" once to do the installation

I had the exact same error on my PC (I just freshly reinstalled my PC with Vista 64 and decided to give the latest MM beta a try instead of 3.0.7 with the latest last.fm scrobbler as well.

Reading Peke's post, going to the MM shortcut and selecting "always run as admin" did it for me and allowed the plugin to install instead of getting the error message. I didn't even deactivate UAC yet, as I said, I'm in the middle of reinstalling everything in Vista :p, so my Vista is as default as it gets atm (with all the updates installed though).

Interesting I can't Reproduce. Have you checked MM shortcut properties -> compatibility -> run always as admin? What do you mean do not work at all?

Can you go into Windows Folder and start windows explorer as administrator and then try?

Also all users folder should be accessible for all as MM save extension installations there.

I've tried that - I still get the "Product Installation Error" when MM is running normally. If I run MM as Administrator, the drag and drop doesn't work at all.

Have you tried to Drag and Drop .MMIP to MediaMonkey Player?

I'm running Vista Ultimate. I am an Administrator, UAC off, I've run Mediamonkey.exe as an Administrator - yet I still get "Product Installation Error" when I try installing the Last.fm scrobbler. There doesn't seem to be any way around this.

Also - double clicking the *.mmip file when Mediamonkey is running as Administrator invokes a second instance, even with the "Allow only one instance of Mediamonkey" checked in the preferences.

Is there any work around for this? I'd love to get last.fm working.

I'm running MM 3.1.0.1236 and trying to install last.fm scrobbler 1.0.2.14