IIRC you need to have an account with Cherry Audio in order to activate the VST.
It's a while since i used MMM but i'm sure i had to create an account on the Cherry Audio site in order to use Polymode which i purchased on the Music Maker store.
Again, recalling from memory, you have to set the account and register the serial number (from the MM store) which then allows you to activate the VST in Music Maker - when you launch the vst (for the first time) you get a pop up box in which you enter the user name / password from the Cherry Audio account. The VST then launches
Just tried it myself and i'm getting the same issue as you.......i have logged into my Cherry Audio account ( and my serial numbers are listed there) but i cannot get the VST's to launch in MMM. ( i get the same message )
Just for your information: This was an issue caused recently by some changes for the Cherry Audio items on the end of the in-app store system and has now been fixed again via the latest Music Maker patch:
Technical background: The Cherry Audio instruments are never deployed automatically via Music Maker's in-app store system. It always takes the licensing, download and installation procedure via the Cherry Audio website. Due to the way their installer works, it cannot be automated and integrated as seamlessly as our own or other some other third-party instruments. When you click the install option for purchased Cherry Audio instruments, it will bring up your purchased serial number and the set of instructions. This is now working again with the new patch.
Once installed via the Cherry Audio website and installer, those plug-ins will integrate like any other third-party ones. So, depending on where you installed them on your machine, you may or may not need to manually add a VST plug-in scan path to your Music Maker settings.