Error running the Demo

I downloaded the demo WebGMaps ( and compiled the demo.

When I executed the demo app -- it gave me an error stating

Error Reading WebGMap1.Clusters : property Clusters does not exists

In Design mode everything seems fine...  

What could be the problem

Can it be a previous version was not fully / correctly uninstalled?
Can you search & delete old version files? 
Can you open all forms using TWebGMaps in your application in the IDE, ignore any possible property errors, save the form files and then rebuild the application?